interlocking in railway signalling circiut

7/25/2019 Interlocking in Railway Signalling Circiut

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CHAPTER- I

INTRODUCTION

1.1 Introduction to Interlocking

In railway signalling, an interlockingis an arrangement of signal apparatus that prevents

conflicting movements through an arrangement of tracks such as junctions or crossings.

The signalling appliances and tracks are sometimes collectively referred to as an

interlocking plant. An interlocking is designed so that it is impossible to display a signal

to proceed unless the route to be used is proven safe.

Fig 1.1 Interlocking

Types o Interlocking!

1.1.1 "ec#$nic$l interlocking

1.1.% Electro-&ec#$nic$l interlocking

1.1.' Rel$y interlocking

1.1.( Electronic interlocking

1.% )ign$ls

ignal is a medium to convey a particular pre!determined meaning in non!verbal form.

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1.%.1 "ultiple Aspect Color *ig#t )ign$l +"AC*),!

"ultiple means more than # indications .They may have $ or % different aspects or

indications to be given to the driver. These signals have longer range of visibility and

Improved reliability.

1.%.% Cl$ssiic$tion o C*)!

1.%.' "$nu$l )top )ign$l !

&ach aspect of the signal is represented by a circle. A hori'ontal line inside the circle

indicates (ed aspect, an inclined line the yellow aspect and vertical line the )reen aspect.

The normal aspect of the signal is shown by double line.

1.%.( Per&issie )ign$l +Dist$nt )ign$l, !

hall be located at an ade*uate distance in rear of the stop signal, the aspect of which it

pre! warns.

1.%. Auto&$tic )top )ign$l !

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The normal aspect of an automatic signal is green and is indicated by the double vertical

line, unlike the manual signal where the normal aspect is red and indicated by double

hori'ontal lines.

1.%./ )e&i-$uto&$tic )top )ign$l !

An illuminated +A marker distinguishes a semi - automatic signal from a fully automatic

signal. etter +A against black back ground is illuminated when working as an automatic

stop signal and letter +A e/tinguished when working as a manual stop signal.

1.%.0 $te )ign$l !

The )ate stop signal shall be provided with +) marker. etter +) in black on a yellow

circular disc.A semi!automatic stop signal interlocked with a level!crossing gate shall be

provided with +) marker disc and an illuminated +A marker. The +A marker shall be lit

only when the gates are closed and locked against road traffic.

1.' "icrolok-II )yste&!

"icrolok II interlocking control system is a multi!purpose monitoring and control system

which is designed for rail mass transit wayside interlocking functions such as switch

machine and signal lamp control, track circuit occupancy monitoring and non vital code

line communications.

1.'.1 )yste& Co&ponents

The "icrolok II interlocking control system is a multi!purpose monitoring and control

system designed for railroad and rail mass transit wayside interlocking functions such as

switch machine and signal lamp control, track circuit occupancy monitoring, and non!

vital code line communications.

The 0omponents isted elow2

o The system card file

o 034 30 board

o 5ital inputs and output 30

o 6on!vital I78 30

o 3ower supply 30o 508( (elay

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o Address elect 30

o &&3(8" 30

o Terminals

o urge uppressor

CHAPTER -%

*ITERATURE )UR2E3 RE*ATED 4ITH TRAININ

%.1 INTER*OC5IN

%.1.1 Introduction

In railway signalling, an interlockingis an arrangement of signal apparatus that prevents

conflicting movements through an arrangement of tracks such as junctions or crossings.

The signalling appliances and tracks are sometimes collectively referred to as an

interlocking plant. An interlocking is designed so that it is impossible to display a signal to

proceed unless the route to be used is proven safe.

Fig!#.1Interlocking

An interlockis a device used to prevent undesired states in a state machine, which in a

general sense can include any electrical, electronic, or mechanical device or system. In

most applications an interlock is used to help prevent a machine from harming its

operator or damaging itself by stopping the machine when tripped.

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%.1.% Types o Interlocking

%.1.%.1 "ec#$nic$l interlocking

In mechanical interlocking plants, a locking bedis constructed, consisting of steel bars

forming a grid. The levers that operate switches, derails, signals or other appliances are

connected to the bars running in one direction. The bars are constructed so that, if the

function controlled by a given lever conflicts with that controlled by another lever,

mechanical interference is set up in the cross locking between the two bars, in turn

preventing the conflicting lever movement from being made.

In purely mechanical plants, the levers operate the field devices, such as signals, directly

via a mechanical rodding or wire connection. The levers are about shoulder height since

they must supply a mechanical advantage for the operator. 0ross locking of levers was

effected such that the e/tra leverage could not defeat the locking 9preliminary latch lock:.

The first mechanical interlocking was installed in 1;%$ at ricklayers< Arms

=unction, &ngland.

Fig!#.#!"echanical interlocking

%.1.1.1 Electro-&ec#$nic$l interlocking

3ower interlockings may also use mechanical locking to ensure the proper se*uencing of

levers, but the levers are considerably smaller as they themselves do not directly control

the field devices. If the lever is free to move based on the locking bed, contacts on the

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levers actuate the switches and signals which are operated electrically or electro!

pneumatically. efore a control lever may be moved into a position which would release

other levers, an indication must be received from the field element that it has actually

moved into the position re*uested. The locking bed shown is for a )( power

interlocking machine.

%.1.1.% Rel$y interlocking

Interlockings effected purely electrically 9sometimes referred to as ?all-electric@: consist of

comple/ circuitry made up of relays in an arrangement of relay logic that ascertain the

state or position of each signal appliance. As appliances are operated, their change of

position opens some circuits that lock out other appliances that would conflict with the

new position. imilarly, other circuits are closed when the appliances they control become

safe to operate. &*uipment used for railroad ignaling tends to be e/pensive because of its

speciali'ed nature and fail!safe design.

Interlockings operated solely by electrical circuitry may be operated locally or remotely

with the large mechanical levers of previous systems being replaced by buttons, switches

or toggles on a panel or video interface. uch an interlocking may also be designed to

operate without a human operator. These arrangements are termed automatic

interlockings, and the approach of a train sets its own route automatically, provided no

conflicting movements are in progress.

)( manufactured the first all!relay interlocking system in 1B#B. It was installed in

incoln, 6ebraska on the 0hicago, urlington and Cuincy (ailroad.

Fig!#.$2(elay interlocking
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%.1.%.( Electronic interlocking

"odern interlockings 9those installed since the late 1B;Ds: are generally solid state, where

the wired networks of relays are replaced by software logic running on special!purpose

control hardware. The fact that the logic is implemented by software rather than hard!

wired circuitry greatly facilitates the ability to make modifications when needed by

reprogramming rather than rewiring. In many implementations this vital logic is stored as

firmware or in (8" that cannot be easily altered to both resist unsafe modification and

meet regulatory safety testing re*uirements.

Fig!#.%2&lectronic interlocking

At this time there were also changes in the systems that controlled interlockings. Ehereas

before technologies such as 6 and Automatic (oute etting re*uired racks and racks of

relays and other devices, solid state software based systems could handle such functions

with less cost and physical footprint. Initially processor driven 4nit ever and 6 panels

could be set up to command field e*uipment of either electronic or relay typeG however as

display technology improved, these hard wired physical devices could be updated with

visual display units, which allowed changes in field e*uipment be represented to the

signaller without any hardware modifications.

%.1.1 6or&s o *ocking

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%.1.1.1 Electric locking

The combination of one or more electric locks or controlling circuits by means of which

levers in an interlocking machine, or switches or other devices operated in connection

with signalling and interlocking, are secured against operation under certain conditions.

%.1.1.% )ection locking

&lectric locking effective while a train occupies a given section of a route and adapted to

prevent manipulation of levers that would endanger the train while it is within that

section.

%.1.1.' Route locking

&lectric locking taking effect when a train passes a signal and adapted to prevent

manipulation of levers that would endanger the train while it is within the limits of the

route entered.

%.1.1.( )ection$l route locking

(oute locking so arranged that a train, in clearing each section of the route, releases the

locking affecting that section.

%.1.1. Appro$c# locking

&lectric locking effective while a train is approaching a signal that has been set for it to

proceed and adapted to prevent manipulation of levers or devices that would endanger

that train.

%.1.1./ )tick locking

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&lectric locking taking effect upon the setting of a signal for a train to proceed, released

by a passing train, and adapted to prevent manipulation of levers that would endanger an

approaching train.

%.1.1.0 Indic$tion locking

&lectric locking adapted to prevent any manipulation of levers that would bring about an

unsafe condition in case a signal, switch, or other operated device fails to make a

movement corresponding with that of the operating leverG or adapted directly to prevent

the operation of one device in case another device, to be operated first, fails to make the

re*uired movement.

%.1.1.7 C#eck locking or tr$ic locking

&lectric locking that enforces cooperation between the 8perators at two adjacent plants in

such a manner that prevents opposing signals governing the same track from being set to

proceed at the same time. In addition, after a signal has been cleared and accepted by a

train, check locking prevents an opposing signal at the adjacent interlocking plant from

being cleared until the train has passed through that plant.

%.%Tr$ck CircuitsTrack circuits are electrical circuits that are formed including the running rails. They are

set up in such a way that when a train is on the tracks that are part of the track circuit, the

circuit is altered in some way 9usually, by current that normally flows in the track circuit

being shunted through the conductive body of the train:, thereby activating a detector

which may then be used, e.g., to set signals at danger for the section.

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Fig!#.>2Tracking 0irciut

Track circuits help with interlocked operation as they allow signals to be pulled off only if

the section of track they control is safely clear of any vehicles. They also remove the

human element of needing to scrutini'e the track for the presence of trains that may be

out of view of the signalling staff or cabin men.

&ach circuit detects a defined section of track, such as a block. These sections are

separated by insulated joints, usually in both rails. To prevent one circuit from falsely

powering another in the event of insulation failure, the electrical polarity is usually

reversed from section to section. 0ircuits are powered at low voltages 91.> to 1# 5 0: to

protect against line power failures.

%.'PRINCIP*E) O6 TRAIN 4OR5IN

All over the world (ailway transportation is increasingly used, as this mode of transport

is more energy efficient and environmentally friendly than road transportation. Trains

move on steel rail tracks and wheels of the railway vehicle are also flanged teel wheels.

Jence least friction occurs at the point of contact between the track K wheels.

%.'.1 Need o )ign$lling!

There are basically two purposes achieved by railway signalling.

1 To safety receive and despatch trains at a station.

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# To control the movements of trains from one station to another after ensuring that the

track on which this train will move to reach the ne/t station is free from movement of

another train either in the same or opposite direction. This 0ontrol is called block

working. 3reventing the movement from opposite direction is necessary in single line

track as movements in both directions will be on the same track.

%.'.% T#e essenti$l co&ponents o r$il8$y sign$lling!

The fi/ed signals provided by the side of the railway track with indication in the form of

colour lights are the actual authority to a driver to get in to the portion of the track beyond

the signal. At stations the trains may be received on any one of the platform lines. To take

the train to any specific track, points are provided.

%.(9A)IC TRAC5 )TRUCTURE!

Trains run on dedicated line .A line consists of two rails running parallel to each other.

Fig!#.2asic Track turcture

This is also called Track. The width of the track is > @in road gauge 9.): In station

yards there will be more than one track for receiving and dispatching trains. 3oints are

provided to divert the running trains from one track to another. The points have movable

switches which can be operated electrically by a point &$c#ine.

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Fig!#.H2 Track Eith 3oint "achine

%.(.1 Cle$r$nce o tr$ck!

ince a train cannot be received on the portion of track where another train is standing on

same portion of the track, the signal before it is cleared for the movement of a train has to

ensure the track clearance. There are e*uipments used in (ailway signaling to achieve the

above safety condition.

%.)INA*)

ignal is a medium to convey a particular pre!determined meaning in non!verbal form.

%..1 "ultiple Aspect Color *ig#t )ign$l +"AC*),!

"ultiple means more than # indications .They may have $ or % different aspects or

indications to be given to the driver. These signals have longer range of visibility and

Improved reliability.

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%..% Cl$ssiic$tion o C*)!

Fig!#.; 0lassification of 0

%..%.1 "$nu$l )top )ign$l !

&ach aspect of the signal is represented by a circle. A hori'ontal line inside the circle

indicates (ed aspect, an inclined line the yellow aspect and vertical line the )reen aspect.

The normal aspect of the signal is shown by double line.

)reen

Lellow

(ed

Fig!#.B2"anual top ignal

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Table!1.12 "anual top ignal

%..%.% Per&issie )ign$l +Dist$nt )ign$l, !

hall be located at an ade*uate distance in rear of the stop signal, the aspect of which it

pre! warns.

The normal aspect of permissive signal is ingle Lellow where # distant signals are

provided to pre! warn the stop signal, the outer most signal, to be located at an ade*uate

distance from the first stop signal, shall be called the distant signal and the other called

the inner distant signal, with the distant capable of displaying attention or proceed aspect

only.

To distinguish between stop signal and permissive signal +3 marker board 9letter in black

on white board: is fi/ed to the permissive signal.

%..%.' Auto&$tic )top )ign$l !

The normal aspect of an automatic signal is green and is indicated by the double vertical

line, unlike the manual signal where the normal aspect is red and indicated by double

hori'ontal lines.

Fig!#.1D2Automatic gnal

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An automatic signal has an +A marker plate fi/ed to the signal post to distinguish it as an

automatic signal. etter +A in black on white circular disc.

%..%.( )e&i-$uto&$tic )top )ign$l !

An illuminated +A marker distinguishes a semi - automatic signal from a fully automatic

signal. etter +A against black back ground is illuminated when working as an automatic

stop signal and letter +A e/tinguished when working as a manual stop signal .

%..%. $te )ign$l !

The )ate stop signal shall be provided with +) marker. etter +) in black on a yellow

circular disc.

A semi!automatic stop signal interlocked with a level!crossing gate shall be provided with

+) marker disc and an illuminated +A marker. The +A marker shall be lit only when the

gates are closed and locked against road traffic.

Fig!#.112)ate ignal

%..%./ Routing Indic$tor !

Ehere two are more lines diverge, information is to be given to driver that he is being

received on diverge line. Jence route indicators are provided. (oute indicators are fi/ed

on the first stop signal and starters.

If the route indicator on a signal is not in working order, the relevant signal shall also to

be treated as defective signal.

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(oute indicator is denoted as 94):.

Route indic$tor $re o t#ree types.!

%..%./.1 :unction type route indic$tor !

4sed where the speed is above 1>M"3J

It is having a provision of indicating si/ diversions and a straight line.

Ehen taken off it shows a row of five white lines.

%..%./.% "ulti l$&p route indic$tor !

4sed where the speed is less than 1> M"3J.

It can e/hibit nine numerals and alphabets.

%..%./.' )tencil type route indic$tor !

6ormally fi/ed on starter signal.

%..%.0 )u;sidi$ry )ign$ls

ignals are used for reception of trains in to a station and despatch of trains out of station.

ignals used for movement of trains within the station section at restricted speed and for

special purpose are called ubsidiary signals. In "A0 signalling hunt signals and

0alling-on signals come under subsidiary signals.

%..%.0.1 )#unt sign$l!

It is of position light type, The lights shall be white in colour. hunt signals control

shunting movements. A shunt signal may be placed on a post by itself or below a stop

signal other than the first stop signal of a station. Ehen a shunt signal is taken N8FF , it

authori'es the driver to draw ahead with caution for shunting purposes although stop

signal, if any, above it is at +86. Ehen a shunt signal is placed below a stop signal, it

shall show no light in the +86 position.

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%..%.0.% C$lling-on sign$l!

A 0alling!on signal has no independent location and displays no aspect in +86 position.

A calling!on signal where provided, shall be fi/ed below a stop signal governing the

approach of a train with +0 marker board fi/ed to the signal post. A calling!on signal

when taken +8FF it displays a miniature yellow light.

4nder approved special instructions, a calling!on signal may be provided below any other

stop signal e/cept the last stop signal.

Fig!#.1#2 0alling on ignal

Ehen placed below a stop signal, it shall show no light in the +86 position. A calling!on

signal under main signal above it cannot display +8FF aspect at same time.

%./O2ER*AP

&very stop signal by its indication to the driver controls the movement of train upto the

ne/t stop signal as the ne/t stop signal will control the movement beyond it. Jence the

track between the stop signal and the ne/t has to be clear and the points have to be

correctly set and locked before a movement is permitted by it. Jowever due to any

unforeseen reasons like with sudden brake inade*uacy the driver may not be able to stop

at the ne/t stop signal. o an e/tra safety margin of the track beyond the ne/t stop signal

is also to be kept free so that if the train overshoots the ne/t signal, he will be able to

bring the train to stop within that margin. This safety margin is called ?overlap@. imilarly

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we have to ensure that when a train moves on the track the other rail vehicles from the

adjoining track should not roll down and infringe with the movement. To prevent this

?isolation@ between adjoining lines is re*uired.

8verlaps are referred to as A&C4AT& distance. 8verlaps are of two types2

1: lock 8ver ap 98:

#: ignal 8ver ap 98:

%./.1 9lock oer l$p ! It is the e/tra length of track in advance of the F 9First top

ignal: of a station, which must be kept clear, before ine clear can be given to

the station in rear.

%./.% )ign$l oer l$p !The length of track in advance of a stop signal of station, which

must be kept clear, before the signal ne/t in rear could be taken +8FF.

%.0I)O*ATION

The term isolation denotes the condition in which line for a particular movement of a

train is separated from all adjoining lines connected to it in such a manner that it cannot

be fouled or interfered with by any movement taking place on the adjoining lines.

%.7 )INA*IN P*AN

For any station whether a wayside or a junction, the &ngineering department prepares a

plan depicting all the lines, points, evel 0rossings if any, Foot!over ridge 9F8:, ub!

way if any coming within the station section, ridges if any, gradient etc. This plan is

called as the O3!way 3lanO. This plan is studied by the ignal &ngineers and based on this

a ignalling 3lan is prepared indicating the following2

All gradients with in the station limit on either side upto #.> Mms.

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Milometer and class of level crossing gate within the station limits, whether interlocked

or not.

4p K n direction, 6ame of important junction and immediate station on either side.

ocation of signals, with reference to point and level crossing gate.

"arking of signals, points and level crossing gates.

Inter signal distances and distance between warning boards K signals

Type of lock working with adjacent station and location of lock instrument.

Type of turnouts.

escription of siding.

(estriction on dead end sidings.

0rank handle details.

etails of A/le counters 7 Track circuits.

ignalling 8ver lap.

Jolding capacity of all running lines and sidings. 6ote regarding telephone communication provided between A" and evel crossing

with in and out of station section.

(eference to approved engineering plan on which the signalling plan is based.

0( s dispensation for deviation from )K( 7 &", if any.

Aspect se*uence chart for 0.

6ame of the station, tandard of station.

0lass of station, 0entre line with kilometers, 6orth point.

6ames of the stations with distance on either end of the station.

3anel position 7 " s control, with spare knobs 7 slides.

etection table.

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%.11 TRAC5 CIRCUIT)

Track circuit is a vehicle detection device in which the running rails form part of an

electrical circuit. The boundaries of track circuit are marked by insulation joints on the

rail and rails are bonded at rail joints for better conductivity.

4ses of Track 0ircuits2

For detecting the presence of vehicles or absence of vehicles within the limits of the

track circuits.

For locking the point when train is on the point.

Trolley protection circuit for a/le counter to ensure wheels of easily removable trolleys

are not counted.

%.11.1 Closed Tr$ck Circuit !

In this type current is always flowing through the relay. Ehen train comes over the track,

the supply to the relay is shunted and the relay de!energi'es. The smallest closed track

circuit provided is of # meter length. The longest workable track circuit depends on the

allast (esistance 9i.e., (esistance across rails offered by the stone chips placed below

the rail to support track:, This ballast decides the leakage current. In other words ballast

resistance appears across or in parallel with relay coil resistance.

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%.11.% Open Tr$ck Circuit!

8pen track circuit is one in which the track relay is normally de!energi'ed and picks up

only when train comes on the track. In this track circuit any disconnection with train on

the track will drop the relay and failure on unsafe side will take place, as the relay will

show track is clear under occupation. Jence this track circuit can be used for short length

only i.e., # "ts. 6ow a days open track circuits are not used.

Fig!#.1$!8pen Tracking 0ircuit

%.11.' 6ed oer tr$ck circuit!

It is a sub division of track circuit. This is generally adopted when it is not possible to

work a long track due to inability to maintain prescribed parameters like ballast resistance

for fail safe working of track circuit.

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Instead of dividing it in to independent track circuits, the first track circuit is fed by the

usual battery and relay arrangement. The feed to the second track is taken through the

front contact of the track relay which controls the first track and so on. The last track

relay can serve to indicate occupancy or clearance of the portions of all track circuits.

Fig!#.1%2 Fed over tracking 0irciut

%.1% E*ECTRICA* POINT "ACHINE

An electrical point machine is an electrically driven motor used for operation of points in

railway yards. The rotary motion of the motor is transmitted through the reduction gears

and transmission assembly and converted through linear movement of a toothed rack

through a pinion. The gear rack drives switch rails to unlock, change the position from 6

to ( or ( to 6 and lock the switch at the end of the stroke.

e*uence of point machine operation2

8pening of the detection contacts.

4nlock the points.

"ove the points to the desired position

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ock the points.

0lose the detection contacts.

%.1' A>*E COUNTER

%.1'.1 Co&p$rison 8it# tr$ck circuit!

To detect the presence of vehicle within a prescribed distance is the role of track

circuit.

ropping of track relay is due to shorting of rails by the a/les of a vehicle train.

%.1'.% 6e$tures o A?le counter!

It works on magnetic flu/ variation on a ground device for counting the a/les and

electronic circuits to evaluate in!count and out!count. To detect the presence of wheel.

%.1( INTER*OC5IN

"eans an arrangement of signals , points and other appliances, operated from a pane or

from lever frame, so interconnected by mechanical locking or electrical locking or both

that their operation must take place in proper se*uence to ensure safety.

%.1(.1 Electric$l *ockings

%.1(.1.1 Route locking!

After a route is set 9that is, the points in the route are operated to the position as re*uired

for the route:, it is electrically locked before the signal is cleared. y this we mean the

points in the route are electrically locked and they cannot be operated for any other route

till such time the route that is locked is released and the points become free for operation.

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%.1(.1.% Route &olding!

8nce a route is set, locked and the signal is cleared for a train, it must be held till such

time the train is received on the berthing track or the route is released by an emergency

route release operation.

%.1(.1.' Tr$ck locking!

It is an electrical locking on a point which prevents the operation of the point when a train

occupies the track circuit provided over the point.

Ehen a train is on >1 AT or >1T, the respective track relay will be de!energi'ed. 4nder

this condition, it is not possible to operate the point either by route initiation or by

individual operation. Ee say the point is track locked.

%.1(.1.( Indic$tion locking!

It is an electrical locking so provided as to ensure that after the reception of the train on

the berthing track the route is not released unless it is proved that the signal which was

cleared for receiving the train has gone back to danger and all the signal control relays

have de!energi'ed.

%.1(.1. Appro$c# locking!

It is an electrical locking effective while a train is approaching a cleared signal and

adopted to prevent releasing of the route when the train is within a ?3re!determined

distance@ from the signal.

Fig!#.1>2 Approach ocking

For the purpose of providing approach locking on the signal, a track circuit called

?Approach Track@ 9AT: needs to be provided to a length of 1!# kms

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%.1(.1./ De$d $ppro$c# locking!

It is seen that for providing approach locking, a track circuit for a length of 1,#kms. 6eed

to be provided. 3rovision of such a long track circuit for the purpose of approach locking

is a costly proposition. Therefore, the approach locking is provided without the approach

locking becomes effective the moment the signal is cleared irrespective of the position of

the train in the approach.

%.1(.1.0 9$ck locking or route locking!

It is an electrical locking effective when a train has passed the signal and adopted to

prevent releasing of the route while the train is ?within the limits of the route entered@.

%.1(.% Rel$y ;$sed Interlocking

(elay Interlocking is a system of implementing principles of interlocking for safe train

operations at a tation with the help of electrical circuits wired through electro!magnetic

relay contacts and coils.

P$rts o )u;-)yste&s o $ Rel$y ;$sed Interlocking!

%.1(.%.1 Indic$tion-cu& Oper$tion P$nel!

This panel shows the miniature lay out of the yard with controlling knobs7buttons for

operating various functions mounted on the panel. This also gives indications about the

status of the functions i.e., 3oints, ignals, (outes, )ate 0ontrol, Track 0ircuits, etc. This

panel is operated by the tation "aster who is in!charge of the Train 8perations at that

tation.

%.1(.%.% Rel$y Roo& !

This consists of racks which are wired and on which the relays are mounted. This is the

interlocking 0entre of the tation. This relay room on one side is connected to the panel

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to receive commands from the panel for operation of the functions and also to give

indication to the panel to show the status of the functions which are controlled by the

interlocking. 8n the other side, this relay interlocking takes inputs from the field like

position of signals, points, track circuits, etc., and gives output to outdoor functions to

drive them.

%.1(.%.' Po8er )upply Roo& !

This consists of 3ower upply units as under2

atteries

attery 0harges

5oltage tabili'ers

Transformers for tepping down the voltages

%.1(.%.( Po8er P$nel !

This is for connecting the different sources of power i.e., Traction, 0ommercial upply,

)enerator upply, etc.

%.1(.%. Outdoor C$;le Ter&in$tions !

ince controls originate from relay room and go to the outside functions like 3oints K

ignals and their status are repeated to relay room, signalling cables are laid from the

(elay (oom to the functions.

%.1(.' T8o-H$nd Oper$tions

1. To ensure that any ignalling gear is operated only by an authori'ed person, the panel

has got a locking arrangement. The key is with the A" on uty. Ehen he leaves the

panel, he has to lock the panel and take the key with him. 8nce the key is out, no

function can be disturbed by any outsider.

#. To ensure that only a deliberate action by the A" operates a signal or a point and no

inadvertent placing of hand on any button will lead to the operation of the function, the

operation of the panel re*uires both the hands. In other words in the 3ush utton

system where an accidental placing of one hand can operate the button for any

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function, i.e., signal or point, two buttons are to be pressed. The buttons are so placed

that with a single hand, the two buttons will not be pressed.

%.1 )E*ECTION TA9*E

The various safety aspects such as interlocking of conflicting routes, re*uirements of

points for each route, the track circuit controls for the points, the route holding

re*uirements such as approach locking and back or route locking and other controls such

as crank handle controls, gate controls, block control and overlap release etc. are first put

in a table called @control t$;le. 8r @selection t$;le and this table is used in the

preparation of circuits.

In the preparation of the control table, the following points should be kept in view2 Ehen

a route is set and locked, it should lock all other conflicting route may be.

A. Directly conlicting route! (oute which re*uire all its points in the same position as

that of the route which is set and locked.

. Indirectly conlicting route! (oute which re*uire at least one of its points in a

different setting from the points of the route which is set and locked.

%.1/ Points control t$;le

The route wise control table does not show the points controlled. &ach point is controlled

by the point track circuits for track locking so that if any train is moving over the points,

the track locking will be effective and the points cannot be operated under the wheels.

This aspect is illustrated separately in a points controlled table.

%.10 E>P*ANATION O6 CIRCUIT)

%.10.1 9utton rel$y circuits

Ee have studied in 0hapter 6o.H, the various features provided in the ?0ontrol cum

Indication 3anel@. &very main and shunt signal has a button provided at the foot of the

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signal symbol on the panel. The route buttons are provided in the middle of the track

configuration for each route. These buttons are also known as e/it buttons or destinations

buttons. 3oint buttons are provided at the point configuration. The various common

buttons such as EE6, &E6, &))6 etc. are fi/ed on the top of the panel. All these

buttons are differently colored for easy distinction.

The various buttons are grouped as follows and the button relay circuits are provided

accordingly2

ignal button relays

(oute button relays

3oint button relays

0ommon button relays

%.10.% Co&&on ;utton rel$y circuit!

The following common buttons for the entire station are grouped in this circuit.

1 08 ))6 ! 0alling on signal button

# &4L6 ! &mergency (oute (elease button.$ ((46 ! uper &mergency (oute (elease utton

% )(6 ! 0ommon 9)eneral: lot (eturn button.

> )6 ! 0ommon 9)eneral: lot button

&856 ! &mergency overlap (elease button.

%.10.' Route )election!

The energisation of )6( K 46( energi'es the route selection relay 9(:, provided that

no conflicting route is set. Thus the basic interlocking is ensured at this first stage itself.

1 ( is designated after the signal number K with route alphabet, if the signal has

more than one route.

# ( is normally down K picks up when an operation to clear a signal is performed

K when the interlocking permits.

$ ( picks up only when the conflicting ( s are not energi'ed.% &nergi'ation of ( operates the points to the desired position..

> ( front contact is used in route checking 940(: K signal control 9J(: circuits.

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%.10.( Point Oper$tion

A point can be operated from normal to reverse or vice versa, as per re*uirement by any

one of the following methods2

1. As a part of route setting for a signal that needs to be cleared.

#. Individual operation of point under normal condition 9i.e., Track 0ircuit

0ontrolling the point is energi'ed:.

$. Individual operation of point when track circuit has failed to energi'e.

%.10. Route C#ecking Rel$y B UCR

The route checking relay 940(: checks that all the points involved in the selected

route are correctly set and locked at the site. It also proves that the route set is for the

signal route initiated including isolation and overlap. 8ne signal will have one 40( K will be designated by the signal number.

It will have parallel paths depending upon the number of routes to which the signal

leads.

40( is normally down.

40( front contact will be proved in J( 0kt.

40( back contact will be proved in A( ckt.

%.10./ Tr$ck )tick Rel$y +T)R,

The T( is controlled by the track circuit ahead of the signal.

6ormally, one T( is provided for each signal controlled by the first track circuit after

the signal.

ometimes, two or three conflicting signals have a common track circuit ahead, a

common T( is provided for these signals.

The T( is normally energi'ed relay under the control of the first track relay. 8nce it

picks up it is kept energi'ed by a stick feed through its own front contact.

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8nce a train passes the signal and drops the first track relay, the stick feed is cut off and

T( drops. This causes (, 40( and signal control relays to de energi'e and prevents

automatic re clearance of the signal.

ubse*uently, when the train clears the first track, the track relay picks up. T( picks

up proving that the 40( and the signal control relays have dropped and sticks.

%.10.0 E&ergency Route Rele$se

After the signal is cleared it is re*uired to cancel the route. Ehen the train is approaching

the signal, emergency route release is done. This is done in two stages. In the first stage,

the signal is cancelled by pressing )6 and &))6. This operation throws the signal to

danger immediately. In the second stage the route release is initiated by pressing )6 and

&4L6. ut the route release can take place only after a time delays of # minutes to

ensure that the train has come to a stop at the foot of the signal. ut, if the train has

passed the signal before # minutes time delay and occupied the track circuits ahead, the

back locking on the route will be effective and the route cannot be released unless the

train clears all the back locking track circuits and arrives fully on the berthing track. In

this case the route is released automatically.

%.10.7 )uper E&ergency C$ncell$tion o Route

After the reception of the train on the berthing track, if any of the back locking track

circuits fail and the track relay does not pick up, the A( relay cannot energi'e and the

route cannot be released. The points remain locked in the route and other routes over the

points cannot be set. The route can be released only after the track circuit.

Failure is rectified and the A( is energi'ed. This may take considerable time and the

train traffic will be held up. To avoid delay to the traffic a provision has been made on the

panel to release the route even under the back locking track circuit failure condition. This

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is an unsafe provision in the sense that the " may release the route even when the train

is actually moving over the back locking track circuits. 8nce the route is released the

points become free and can be operated under the wheels which may cause derailment.

%.10.< Oerl$p *ocking And Rele$se

For locking the overlap points 85( relay is provided. This is also a normally

energi'ed relay like A(. Ehen A( drops, 85( also drops and locks the

overlap points. This relay can be provided individually for the overlaps. Ehere #

or $ overlaps conflict with one another, a combined 85( can be provided as

only one overlap can be set at a time.

%.10.1= Indic$tions on t#e p$nel 6$ilure $l$r&s $nd e&ergency counters!

%.10.1=.1 )ign$l indic$tions!

Aspects that are e/hibited at each signal are indicated in their respective positions. A

flashing indication is given under lamp failure.

%.10.1=.% Tr$ck indic$tions!

Track strip indications are lit by a white light when a route is set K locked, through the

back contact of A(. epending upon the point position, corresponding indication

strips are lit.

%.10.1=.' Point indic$tion

3oint indications are given by means of two white lights one each at the main ends of

cross over when normal K two white lights on the cross over when set for reverse Ehen

none of the point detections is available either during operation or under failure condition,

these indications are made to flash through 6EM( K (EM( down contacts.

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%.10.1=.( 6$ilure Indic$tions

The various button relays are grouped function wise and a common button normal

checking relay for each group as )60(, 460( and E60(T provided. Ehen any button

fails or button relay fails the button normal checking relay of that group drops and gives

indication of the panel. imilarly for giving indication and alarm for the failure of the

common buttons or their relays, a relay called )(( is energi'ed through the back

contacts of these 0ommon button relays.

%.10.1=. Cr$nk #$ndle Interlocking

Ehen the crank handle is inside &MT, key in contact is made. M6( picks up proving

crank handle in.

If E(T, the point is free from any signal locking. If 0J1 button and common button

)6 are pressed together, 0J1PL( will pick up K hold through its own front contact, as

buttons will be released.

%.10.11*eel Crossing Interlocking

0onnected (elays2

(2 This relay picks up by proving all concerned A(785(s of signals in whose

route7overlap the .0. gate falls are free.9i.e., picked up: and 40(s are de!energi'ed

9i.e., route is not set:.

((2 It proves that the gate is free to be opened for road traffic 9i.e., ( is up:

and gate button 6 and common 9group: slot release button )6 are pressed. It

proves permission is given from the panel to open the gate. Its repeater at the gate is

(3(, the front contact of which gives feed to gate key lock to release it.

M6(2 3roves gate key is in. i.e., gate is closed against road traffic, locked and key is

kept in the place at gate lodge to transfer control to panel at the station. It is the relay in

station, repeating another relay M6Q( at gate site. M6Q( picks up after key is

deposited at site by gate man.

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6(2 This relay proves control given to the gate has come back to panel and gate can

not be opened. After M6( picks up, panel operator presses 6 R )(6 9)roup slot

restoration button: and 6( picks up.

%.17 )3)TE") O6 9*OC5 4OR5IN

The entry of train onto the block section is jointly controlled by the entry and e/it points

of the block section. The driver is authori'ed to proceed into block section by the signal

controlling the entry into the section. This working could be the A84T& 80M

system stem or A4T8"ATI0 80M system.

%.17.1 Essenti$ls o A;solute ;lock !

Ehere trains are worked on absolute block system

a: 6o train shall be allowed to leave a block station unless ine clear has been received

from the block station in advance, andb: 8n double lines, such line clear shall not be given unless the line is clear not only upto

the first stop signal at the block station at which such line clear is given but also for an

ade*uate distance beyond it .

c: 8n single, such shall not be given unless the line is clear of trains running in the same

direction not only upto the first stop signal at the block station at which such line clear

is given but also for an ade*uate distance beyond it, and is clear of trains running in the

direction towards the block section to which such line clear is given. The ade*uate

distance referred shall not be less than 1;D "ts

d: The whole of the last preceding train has arrived completeG and all necessary signals

have been put back to N86 behind the said train.

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e: Fig!#.12 ystem 8f locking Eorking

%.1< AUDIO 6RE. TRAC5IN CIRCUIT

%.1 kJ'

for train detection for each track circuit which is coded on and off by a low fre*uency

code rate between # J' and #1.> J'. Furthermore, a uni*ue carrier fre*uency for train

cab signal transmission is coded on and off in the $ J' to #1.> J' range. These cab signal

carrier fre*uencies vary throughout the transit property. The actual cab signal speed

command transmitted to the train is determined by si/ different code rates.

Fig.!#.1H2A4I8 F(&C. T(A0MI6) 0I(04IT

AF track circuits have the uni*ue advantage of eliminating insulated rail joints at track

circuit boundaries, e/cept at interlocking boundaries, and using both running rails for

negative propulsion return.

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transmitter to receiver is continuously flows in condition of there is no train. Ehenever a

train approaches on the rails where AFT0 is installed because of train the flow of current

breaks because of short circuiting and the train is detected.

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Fig!#.1;2 Train 3rotecion Earning ystemdistance between the arming loop and the trigger loop. This time period provides a speed

test. If the test indicates the train is travelling too fast, a full brake application will be

initiated. In case the train passes the speed test successfully at the first pair of loops but

then fails to stop at the signal, the second set of loops at the signal will cause a brake

application. In this case, both loops are together 9see photo ! right: so that, if a train

passes over them, the time elapsed will be so short that the brake application will be

initiated at any speed.

Fig!#.1BEorking of T3E

%.%=.% Oper$tion

T3E has certain features which allow it to provide an additional level of safety over the

e/isting AE system but it has certain limitations and does not provide the absolute safety

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37/88

of a full Automatic Train 3rotection 9AT3: system. Ehat T3E does is reduce the speed

at which a train approaches a stop signal if the driver fails to get the speed of the train

under control to allow him to stop at the signal. If the approach speed is too fast, T3E

will apply a full brake but the train may still overrun the signal. Fortunately, since the train

is already braking and there is usually a OcushionO of #DD yards 91;$ metres: between the

signal and the block it is protecting, there will be a much reduced risk of damage 9human

and property wise: if the train hits anything. Eith a possible total distance of #DDD feet

9about DD m: between the brake initiation and the block entrance, trains OhittingO the first

loops at up to 1#D km7h 9H>mph: could be stopped safely.T3E is also provided at many 9about $DDD: 3ermanent peed (estrictions 93(s: to

ensure that a train does not pass through a restricted section of line 9say one with a sharp

curve: at too high a speed. Jowever, there have been a number of issues related to the use

of T3E in these cases. rivers have complained that, although they were approaching the

3( at a speed which would allow the train to run at the correct speed within the

restriction, they still got stopped by the T3E Ospeed trapO. This has led to some vigorus

discussions between 6etwork (ail, the train operating companies and the J&.

An add!on to T3E, called T3ER is provided at certain signals where train speeds are

above 1DD mph or 1Dkm7h.

The safety effects of T3E are limited by the fact that it is provided only for stop signals

and that it cannot have any effect at caution signals. This means that there is a range of

speeds at the higher level which will be e/cluded from full protection. In spite of this, it is

suggested in published data that D of accidents due to 3As will be prevented by the

installation of T3E at critical locations. This is achieved, it is said, at 1D of the

installation costs of a full AT3 system.

T3E does not replace the e/isting AE system. AE is retained, so the driver will still

get the warnings advising him of adverse signals. The T3E e*uipment is designed to

interface with the e/isting on!board wiring of trains so that it can be fitted *uickly.

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%.%=.' P$rts o TP4)

%.%=.'.1 9A*I)E

A ;$lise is an electronic beacon or transponder placed between the rails of a railway as

part of an Automatic Train 3rotection 9AT3: system. The French word ObaliseO is used to

distinguish these beacons from other kinds of beacon .

A balise typically needs no power source. In response to radio fre*uency energy broadcast

by a alise Transmission "odule mounted under a passing train, the balise either

transmits information to the train 9


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Fig!#.#D2 alise

A fi/ed balise is programmed to transmit the same data to every train. Information

transmitted by a fi/ed balise typically includes2 the location of the baliseG the geometry of

the line, such as curves and gradientsG and any speed restrictions. The programming is

performed using a wireless programming device. Thus a fi/ed balise can notify a train of

its e/act location, and the distance to the ne/t signal, and can warn of any speed

restrictions.

A controllable balise is connected to a ine side &lectronics 4nit 9&4:, which transmits

dynamic data to the train, such as signal indications. alises forming part of an &T0

evel 1 signalling system employ this capability. The &4 integrates with the

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conventional 9national: signal system either by connecting to the line side railway signal

or to the signalling control tower.

alises must be deployed in pairs so that the train can distinguish the direction of travel

1U# from direction #U1, unless they are linked to a previous balise group in which case

they can contain only one 91: balise. &/tra balises 9up to ; per group: can be installed if

the volume of data is too great.

alises operate with e*uipment on the train to provide a system that enhances the safety

of train operation2 at the approaches to stations with multiple platforms fi/ed balises may

be deployed, as a more accurate supplement to )3, to enable safe operation of automatic

selective door opening.%.%=.'.% 9T"

T3E 9Train 3rotection and Earning ystem:, term used by Indian (ailways, It applies

to the &T0 evel 1 concepts and the 4I0746II) specifications. It does not in Indi$n

ter&s $pply to t#e U5 i&ple&ent$tion t#$t is ;$sed on dierent tec#nology.

The T3E project on outhern (ailway installed in the 0hennai 0entral7 0hennai each

- )ummidipundi section of 0hennai division was commissioned on #nd "ay #DD; on

% &"4 rakes to begin with. The works on the balance $H rakes were progressively

completed in the ne/t few months. 3resently all the %1 rakes proposed to be provided with

T3E on!board e*uipments are functional. The T3E track side e*uipments in the

section were fully provided, commissioned and made functional right from the date of

commissioning.

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Fig!#.#12T"

Table2#.#2T" ystemPro;le&s!

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This T3E project based on the &uropean Train 0ontrol ystem 9&T0: evel!I system

faced many hurdles during the initial installation, proto!type testing, obtaining

the re*uired clearances from (8 and 0(. The major problems noticed during initial

revenue service included

1. 8n!oard system not booting.

#. 8n!oard system going into ystem failure 9F: during booting.

$. "I 9 implified river "achine Interface: going blank.

%. peed display bouncing on the "I leading to braking.

>. rake application in the rear non!driving motor coach on run.

Correctie Actions T$ken ;y R$il8$ys!

%.%1.'.1 Inter&ittent 9T" $ilure!!

Analysis revealed that there was antenna impedance mismatch. The standing wave ratio

9E(: was found more than the tolerance limit of 1.# to 1.%. Interference from &"I was

also suspected. There was problem in communication between the onboard computer

980: and T". The corrective actions for these problems included modifying the

e/isting antenna protection cover and providing copper braided shields for the T/!(/

cable between antenna and T" and for the 08T and 3(8FI4 cable between

80 and T". The T" configuration files were also modified based on some internal

parameters.

%.%1.'.% Error in Tr$in Inter$ce Unit2 !

Analysis revealed that there was problem in communication between some modules of

the 80 and now screened twisted pair cables have been introduced to protect the signals

from e/ternal noise and &"I.

%.%1.'.' Error in )peed )ensor!!

To improve the performance of the 8dometric system, the signal cables between 80

and speed sensors have been provided with copper braided shield firmly connected to the

coach body. To suppress the noise in the 11D5 0 voltage derived from the motor coach

battery, a filter has been provided at the input point of the 80. The traction control relay

has been shifted outside the 80 cubicle to reduce &"I. To improve earthing of the

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motor coach body, a >D s* mm copper cable is to be connected between the &"4 body

and its bogie.

%.%1.'.( 9$ck E"6 ro& t#e E9 EP rel$y coils! -

To cover come this problem, the relay coils and & valve solenoid coils to be terminated

with 1;D7#DD5 "85(s and the body of & K relays to be firmly connected to the

coach body.

%.%1.'. E9 $pplic$tion in re$r co$c#!-

To overcome the problem of application of & in the rear coach while running, the brake

interface circuit has been modified to bypass the & when the T3E system in the

sleeping mode 9": i.e., when the cab is not the driving one.

%.%1.'./ )D"I 9l$nking!-

To overcome the problem of "I blanking, its software has been upgraded. Apart from

this, the 80!"I communication cable connector cover which was earlier plastic has

been changed to metallic. The 80!"I communication cable and the "I power

supply cable have been shielded with copper braids firmly connected to the coach body.

A filter has been provided at the 11D 50 input point of the "I to suppress the ripples

in the power supply.

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CHAPTER- '

TRAININ 4OR5

'.1 "ICRO*O5 II )3)TE"

'.1.1 Introduction

"icrolok II interlocking control system is a multi!purpose monitoring and control system

which is designed for rail mass transit wayside interlocking functions such as switch

machine and signal lamp control, track circuit occupancy monitoring and non vital code

line communications.

The "icrolok II system provides control and monitoring functions for all elements of

basic railway vital interlocking. upervision and control of switch machines, switch

locks, signal lamps, searchlight signal mechanisms, and line wire communication circuits

are managed by the vital microprocessor on the system card file 034 board. tandard

vital output boards interface discrete commands from the 034 board to switch machine

relays or other types of vital relays as re*uired. 6on!vital bi!polar output boards interface

034 commands to searchlight signal mechanisms and any other e*uipment re*uiring a

non!vital bi!polar voltage output. 5ital lamp driver boards enable direct lighting of color

light and searchlight signal lamps. 5ital input boards interface various e/ternal circuit

inputs back to the 034 board. Typical vital inputs include searchlight mechanism

position, switch machine correspondence, and interlocking 8 track circuit occupancies.

The "icrolok II system is also capable of interfacing with coded track circuits adjacent to

the controlled interlocking.

The devices included with the system that divide the basic "icrolok II interlocking

control function include a vital cut!off relay 9508(: and an isolation module. The 508(

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relay is controlled by the card file vital outputs such as switch machines and signal lamps.

The microprocessor responds to the failure of a safety critical diagnostics by commanding

the card file power supply board to remove the dc supply to 508( coil.

The isolation module provides the e*uivalent of double break protection of the circuit

when the system is controlling vital relays or interfacing with line circuits in a separate

e*uipment house. The isolation module is also capable of converting a unipolar output to

a bi!polar output.

The main applications and functions of the "icrolok II system include the direct control

of wayside signals in which the color light signals and search light signal mechanisms are

handled and are controlled. Apart from these there are many other applications which

involve "icrolok! II system to play a vital role in signal conditioning and monitoring of

the track circuits.

'.1.% )yste& Co&ponents

The "icrolok II interlocking control system is a multi!purpose monitoring and control

system designed for railroad and rail mass transit wayside interlocking functions such as

switch machine and signal lamp control, track circuit occupancy monitoring, and non!

vital code line communications.

The 0omponents isted elow2

o The system card file

o 034 30 board

o 5ital inputs and output 30

o 6on!vital I78 30

o 3ower supply 30

o 508( (elay

o Address elect 30

o &&3(8" 30

o Terminals

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o urge uppressor

'.1.' )eri$l Co&&unic$tion Circuits

The serial communications 0ircuits is used in "icrolok II applications that re*uire a vital

serial data link between systems in different e*uipment houses or cases. This protects the

serial channels from voltage transients. A single, standoff!mounted printed circuit board

on the panel contains the &IA7current loop conversion circuitry. 4ser devices include a

power on7off switch, a fuse assembly, power status lamps, and communications status

lamps for the current loop half of the interface.

The list of erial 0omm. 0omponents as below2

o ( erial erver7witches

o Fiber 8ptical 0able

o erial to &thernet 0onverter

o 8ptical Fiber "odem

o Isolator K 0onverter

o (!#$#,(!%$#,(!%;>

'.% )3)TE" CO"PONENT)

'.%.1 )yste& C$rd 6ile

The "icrolok II system card file contains the systems central controlling logic and

circuits that interface this logic directly to e/ternal circuits or intermediate units

9"icrolok II track interface panels, for e/ample:. ogic and interface circuits are

contained on the familiar &uro card format plug!in printed circuit boards. The system card

file contains #D card slots, although not all slots will be used in every application. &ach

installed circuit board plugs into a common backplane motherboard. The backplane

distributes circuit board operating power and enables the 034 board to control and

monitor other boards in the card file.

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The specific circuit boards used in each "icrolok II system are determined entirely by the

system application, although typical configurations are recommended to optimi'e

available card file space. 6o particular slot is restricted to a particular board, however the

code system interface printed circuit board 9when used: is typically placed in the far right

slot 9slot #D: because of its non!standard front panel width. In addition, the board

configuration must agree with the configuration defined in the application logic software.

To prevent accidental insertion of a board in the wrong card file slot, each board is

e*uipped with male keying pins.

These pins correspond with keying plugs installed in the associated backplane slot

connector. The keying pins are installed in the field once the board configuration is

determined. everal other restrictions are placed on the installation of the non!vital I78

printed circuit boards and the local control panel. (efer to service manual "!;DD for

specific board installation

rules. In order to allow communications between the 034 board and the other boards in

the card file, each board must have its bus address configured in hardware. This is

accomplished by means of a set of si/ two!position jumpers, mounted at the rear of the

card file in the e/ternal cable7connector housing attached to the top connector of each

board. =umper settings are defined in the application software. 6ot all "icrolok system

card file boards communicate directly with the 034 board through the card file

backplane. 0ertain boards interface to other board which, in turn, communicates with the

034.

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Fig!$.12 0ard File

'.%.%.1 )plit C$rd 6ile!

The split backplane allows two independent 034 and associated circuit boards to be

housed in a single card file, certain "icrolok II applications re*uire that redundant

systems be provided. In order to accommodate this re*uirement a split backplane is

needed. This split backplane has been made from a 1B!slot mother board. An additional

power connector is placed on the split side in the space formerly occupied by slot!#. This

reduced the slot count to 1;. The copper is separated at the center between slot!1D and

slot! 11 with all traces power and ground planes severed.

A brief schematic of the split card!file is shown in the figure. As discussed above it

consists of two 034 slots and similarly twin slots for other printed circuit boards. It is a

special type of card file which can perform multiple operations at once.

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'.%.% CPU 9o$rd

The 034 board contains the central controlling logic and diagnostic monitoring for the

"icrolok II system, and provides serial five data ports. Four of these ports are used for

communication with e/ternal systems. The fifth port enables the connection of a laptop

30 for software maintenance, diagnostics, and data log downloading. This diagnostic port

is terminated at the B!pin connector on the 034 board front panel

The four general purpose ports can be used for vital serial communications with another

"icrolok II system, a "icrolok system, or one of the "icroTra/ systems 9coded track,

end!of!siding or cab signal controller:. For installations where the "icrolok II system is

communicating with another vital system in the same house or case, the ma/imum serial

cable length is >D ft. A modem is re*uired for cables longer than >D ft.

The tandard "icrook II 034 30 performs a variety of functions such as2

o "onitoring e/ternal indications from vital input 30s and non!vital input 30s.

o 3rocessing vital e/ternal indications and e/ecuting logic defined in the Application logic.

o riving vital output 30s as re*uired by the Application logic.

o "onitoring and controlling serial communication ports 9which are links to other

controllers:.

The four general purpose ports can be used for vital serial communications with another "icrolok

II system, a "icrolok system, or one of the "icroTra/ systems 9coded track, end!of!siding or cab

signal controller:.

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Fig!$.$2034 Front panel

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Fig!$.%2034 oard

'.%.' 2it$l Input 9o$rd

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Table2$.125ital Input oard

&ach of the vital input 30s can accept up to 1 isolated inputs. The specifications for

these boards are as follows2

Fig!$.>25itual Input ard

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There are no power connections re*uired through the upper connector. Ehen wiring a

vital input 30 to a relay contact circuit contained in the same house as the "icrolok II

card file, the signal battery may be used as the energy source to activate the inputs.

Terminals designated 9!: may be connected to battery 61# and 1# switched over relay

contacts.

Ehen wiring a vital input 30 to a relay contact circuit outside the "icrolok II house,

use the isolated source that is part of the power supply. This is consistent with the practice

of confining signal battery to the case in which the "icrolok II unit is housed. &/ternal

wiring should be protected with e*uali'er lightning arrestors from line!to!line 94K part

number 6%>1>>#!D1D1: and with high voltage arrestors from line!to!ground 94K part

number 6%>1>>#!D#D1:.

)PECI6ICATION)! +2IA* IFP,

&ach 5ital 8utput 30 is having 1 inputs.

&ach vital input is assigned to the detection of outdoor gear status such as &0(s in

case of signal, EM( in case of points and T3( in case of Track.

ince the inputs are dealing with the detection of outdoor gears they normally

configured with double cutting arrangement.

'.%.( 2it$l Output 9o$rd

Table!$.#25ital 8utbut oard

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&ach of the standard vital output 30s provides up to 1 outputs. The specifications for

these boards are as follows2

8utputs are controlled by ?high side@ software!controlled switches. oads should be

connected from outputs to battery negative. The high side switch is used to connect

battery 9R: to the output.

&ach output is protected with a polyswitch, which acts like a circuit breaker. Ehen the

over current trip point is reached 9appro/imately D.H>A:, the polyswitch switches to a

high impedance. The switch resets to its normal low impedance when the additional load

or short is removed. A short to battery 9!: will trip the polyswitch and cause the 508(

relay to drop, but will not cause any damage. A short to battery 9R: will not cause any

damage, but since this condition is e*uivalent to a false output, the "icrolok II 034 will

cause the 508( relay to drop.

)PECI6ICATION)! +2IA* OFP,

&ach 5ital 8utput 30 is having 1 independent #% 5 outputs.

&ach output is assigned to the final relay which is driving the outdoor signalling

)ears such as J(, ( in case of signal K E6(, E(( in case of points.

ince the output boards are driving outdoor gears, they are continuously monitored by

the 034 and any abnormal voltage present in the output will lead to

ystem reset 7 shutdown to ensure safety.

'.%. Non-2it$l IFO 9o$rd

Two versions of the non!vital 65.I6$#.84T$#, I78 30s are available. The 03 version

961HDDDD1: is designed for use with the optional "icrolok II ocal 0ontrol 3anel 903:

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- 61BD1$D1. This version of the board is fitted with a %;!pin connector on the front and

back. The front connector engages the 03. The remaining I78 91 inputs and ; outputs:

are available on the rear connector. The other version of the 65.I6$#.84T$# board

961HD1>D1: connects each of its $# inputs and outputs to a B!pin connector mounted

on the rear of the board. oth boards are treated as the same type of board in the "icrolok

II application software.

The 65.84T$# 30 provides $# isolated, outputs for control of e/ternal devices such as

indicators and relays. The outputs are divided into two groups of ; outputs and one group

of 1 outputs, each group having a separate bussed common 9negative 0: reference

output. Isolation allows switching power from sources isolated from the "icrolok II

power supply battery. 8utputs are designed to operate at battery voltages between B.> and

$>50. 8utputs switch positive battery and are capable of supplying up to .>A"3.

6ominal voltage drop per output is load dependent and usually less than #.>volts.

The 65.I6$# 30 provides $# isolated e/ternal inputs. The $# inputs are divided into

two groups of ; inputs and one group of 1 inputs, each group having a separate bussed

common 9negative 0: reference input. &/ternal input voltages between and $>50

represent logical ?1@.

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Fig!$.26on!5ital I73 oards

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Ad$nt$ges!

Allow "icrook II systems to interface most types of non!vital e/ternal

devices and circuits.

Ample number of I78 channels meets most application needs.

Isolated 9house!e/ternal circuit: and non!isolated 9house!internal circuit:

versions available.

eparate &s show states of all channels, including $#!channel versions.

i!3olar version available for bi!polar driver circuits 9e.g. searchlight

mechanisms:

All boards service!proven on railroad and transit properties.

'.%./ Po8er )upply

The 61DD$D1 power supply board provides two regulated output voltages that are

needed for the operation of the card file circuitry. The power supply board performs the

following functions2

0onverts the e/ternal supply voltage 9B.; to 1.# 5dc: to regulate R1#5 and R> for

outputs to the system card file internal circuits.

3rovides an isolated source voltage for e/ternal contact sensing. upplies energy to the 508( relay coil under the control of the 034 printed circuit

board.

The power supply board serves a vital role in the fail!safe design of the "icrolok II

system. The "icrolok II 034 board outputs a #>D J' check signal to the power supply

board as long as the diagnostic checks performed continuously by the 034 detect no

internal or e/ternal system faults. Failure of a diagnostic check results in the removal of

the check signal from the power supply board. The power supply board responds by

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removing the hold voltage from the 508( relay coil 9%DDV:. This, in turn, results in

removal of power to all vital system outputs. The regulated R1#5 and R>5 power is

distributed to all system card file printed circuit boards through the card file backplane

bus. oth voltages are used to power board components and circuits. The R1#5 output of

the power supply board is not used as a source for any vital or non!vital outputs. &/ternal

battery power is used for this purpose.

The optional "icrolok II power!off relay provides a means of reporting a commercial

power failure 9serving the battery charger: to the "icrolok II system. The output of this

relay can be tied to a non!vital or vital input.

Fig!$.H23ower upply

'.%.0 2COR Rel$y+2ITA* CUT-O66 RE*A3,

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To ensure ma/imum operational safety in "icrook II!based systems, all vital outputs

9e.g.to switch machines, signals: are routed through a 5ital 0ut!8ff (elay 9508(:,

which is controlled by the systems vital 034 board logic. The 508( is a key part of

AT 4A ?Inherent Fail afety@ design concept, which ensures that all signaling

e*uipment under "icrook II control is downgraded to the most restrictive state in the

event of a critical fault.

The "icrook II 034 board performs constant internal and e/ternal diagnostics and

generates a ?ystem 8M@ check signal as long as diagnostics are satisfactory. Ehile this

signal is present, a 3ower upply 30 output energi'es the 508( coil and keeps the

relays power!carrying contacts closed. In this condition, outputs to switch machines,

signals, etc. are supplied their re*uired operating power. In the event of a non!recoverable

system fault, the 043 sends a command to remove the 3ower upply 34 output, thus

reenergi'ing the 508( coil and cutting off power to the vital outputs. The signaling

system is then reverted to the most restrictive state.

For applications using the standard "icrook II card file, the 508( is typically attached

to rack mounting bars and base adjacent to the card file. For applications using the

"icrook Intermediate or &nd 3oint card files, the 508( is contained inside the card file

in a separate bay ne/t to the 30s. These card files are already e*uipped with a built!in

508( plug!in mounting base.

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Fig!$.;2 508( (elay

&ach card file will have one 5ital 0utoff relay 9508(: to ensure the healthiness of the

system.

508( has F7 dependent contacts each rated for $ Amps.

The 508( contacts are used to control the power to all card file vital outputs.

The 508( is controlled by the 043 board.

Ehen the system is healthy the coil receives voltage from 3 30 on the power supply

board.

8n failure of a safety!critical diagnostic, the 0 supply to the 508( is removed

thereby opening the contacts that provide battery power to the vital output boards.

'.%.7 EEPRO" PC9

&&3(8" 30 which is provided on rear side of the 034 connector to configure various

serial communication ports. Meying plugs are provided in the card file to ensure coding to

each type of cards.

Fig!$.B2 &&3(8" 30

&&3(8" 30

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'.%.< Address )elect PC9

It is wired in every vital and non!vital I78 boards for cpu addressing. The power supply

30 does not have an address select 30 connected to it.

It is installed at rear end of connecter assemblies.

The jumper setting of boards can be found by looking at the configuration menu in

"icrook II maintains tool.

The jumper setting do not depending on the order of boards that happened to appear in

the card file.

'.%.1= Ter&in$ls

3hoeni/ make terminals are used in "icrook II wiring.

8ne in two out type terminals are used for connection between non!vital I78 boards to

panel and vital input board to relay rack and serial communication circuits.

iode type terminals are used for vital o7p board to relay coils.

Two in two out type terminals are used for connection between relay rack to cable

termination rack.

8ne in one out type terminals are used for relay coil to supply negative and power

distribution.

ink and fuse terminals are used for power circuit.

'.%.11 )urge )uppressor

#$D5 A0 to operator 30 and maintenance 30 are connected through surge suppressor to

protect the e*uipment from lighting damages.

'.' )ERIA* CO""UNTICATION CIRCIUT)

'.'.1 R) Co&&unic$tion Ports

'.'.1.% R)-(7 )eri$l Ports

erial ports 1 and # are the (!%;> serial ports. 3ort 1 supports T and (T output

signals and (, 0, and 0T input signals. ata clock signals including transmit

clock 9T0: which may be either an input or an output and receive clock 9(0: which is

an input are present on port 1 but are not currently not supported by the "I0(88M II

e/ecutive. These signals should not be connected. These signals may be supported in a

future release of the "I0(88M II e/ecutive. 3ort # supports T and (T output

signals and ( and 0 input signals.

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&ach (!%;> port signal is transported by a twisted pair of wires labeled as ! and

R 9T! and TR, for e/ample:. 8utputs labeled with a 9!: always connect to

inputs labeled 9!: or 9A:. 8utputs labeled with a 9R: always connect to inputs labeled 9R:

or 9:. ifferential voltage between 9!: and 9R: conductors of a pair is typically 1.> to >

volts with the 9!: conductor negative with respect to the 9R: conductor when the signal is

not asserted. 9For data lines T and (, the *uiescent or unasserted state is identified

as the "A(M state.: In addition, the signal commons 908": for all ports on an (!%;>

communication link must be connected together to e*uali'e potential between signal

commons for the connected units. Ehen two "I0(88M II units powered by the same

battery are serially connected, the connection of serial commons is made through negative

battery and does not have to be made through the serial cable. 6ote that 08" cannot be

connected to frame or earth ground as it is directly connected through the "I0(88M II

power supply to negative vital battery. (!%;> ports should be interconnected using

86L twisted pair cable with an over!all shield. For best performance, the

interconnecting cables should not contain e/tra, unused pairs. Any unused pairs should be

connected together at both ends of the cable and connected to signal common 908": for

best noise immunity. If connected, the shield should be connected to frame ground at one

end of the cable only. 8n the units at each end of the communication circuit, 1#D ohm, W

watt e/ternal load resistors should be placed across the T and (T transmitters and

across the ( and 0 receivers. Any units in!between should simply ?bridge@ the

circuit using a bridging ?stub@ which is as short as possible. 8n a multi!drop

communication circuit 9a circuit to which more than two units are connected:, the 0

input on the master unit should be biased in its unasserted state. This may be done by

connecting %HD ohm, W watt resistors between the 0! input and D5 and between the

0R input and R>5. The load resistor for the master 0 input should be #%D ohms, W

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63/88

watt 9rather than 1#D ohms: to maintain the re*uired circuit impedance for the biased

circuit. If the 0T input on any serial port is available but not used, it should be forced to

its unasserted state. To permanently force an unused (!%;> input to its unasserted state,

the 9R: input should be connected to R>5 and the 9!: input should be connected to

08""86 9D5:. To force an (!%;> input to its asserted state the 9R: input should be

connected to 08""86 9D5: and the 9!: input should be connected to R>5 or R1#5.

'.'.1.% R)-(%' )eri$l Ports

erial port $ is the (!%#$ serial port. erial port $ supports T and (T output signals

and (, 0, and 0T input signals. ata clock signals including transmit clock

9T0: which may be either an input or an output and receive clock 9(0: which is an

input are present but are not currently supported by the "I0(88M II e/ecutive. These

signals should not be connected. These signals may be supported in a future release of the

"I0(88M II e/ecutive.

In an (!%#$ interface, outputs are referenced to signal common 908": while inputs

have their own independent common, receive common 9(08":. ignal outputs are

connected to signal inputs by a single wire as the are in the (!#$# interface but 08" on

each end is connected to (08" on the other end. As this connection of commons does

not e*uali'e potential between the signal commons 908": of the two connected units, an

additional connection must be made between 08" terminals on the connected units. The

*uiescent or inactive state for all signals is between -$. and - volts. 9For data lines

T and (, the *uiescent state is the "A(M state.:. The active state for all signals is

between R$. and R volts. (!%#$ ports should be interconnected using only multi!

conductor cable with an over!all shield. The cable should not contain any twisted pairs.

The serial port commons 908": should be connected using one of the conductors in the

cable 968T the shield:. For best performance, interconnecting cables should not contain

e/tra wires. &/tra wires should be connected together and connected to 08" at both ends

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64/88

for best noise immunity. 6ote that 08" cannot be connected to frame or earth ground as

it is directly connected through the "I0(88M II power supply to negative vital battery.

The cable shield should be connected to frame ground at one end of the cable only. If

0T is not used, it must be forced to its unasserted state. To permanently force an input to

its unasserted state, the input should be connected to !1#5. To force an input to its

asserted state, the input should be connected to R1#5.

(!%#$ ports may be connected to (!#$# ports by strapping 08" and (08"

terminals together on the (!%#$ end and connecting signals as described under the (!

#$# connection scheme below.

'.'.1.' R)-%'% )eri$l Ports

erial port % is the (!#$# serial port. erial port % supports T and (T output signals

and ( and 0 input signals. &ach (!#$# signal is transported by a single wire and

is referenced to signal common 908":. Ehen any (!#$# signal is not asserted the

volta

interlocking in railway signalling circiut

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