irse australasia launceston july 2013 - john skilton - cost effective signalling

7/28/2019 IRSE Australasia Launceston July 2013 - John Skilton - Cost Effective Signalling

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The Institution of Railway Signal Engineers Inc

Australasian Section Incorporated

Cost Effective Signalling – Sweating the Asset in NewZealand

John Skilton

BE Hons. (Electrical and Electronic)

FIRSE, MIPENZ, CPEng

IRSE Australasia Technical Meeting: Launceston 19 July 2013 of 8

SUMMARY

Generations of signalling engineers have been subjected to accusations that signalling is too expensive.This paper examines some of the techniques applied in New Zealand to provide cost effective signalling andtrain control systems. Case studies for the use of common SCADA platforms for train control and the usetraffic light based level crossing systems in yard areas are provided. The paper concludes with a brief look

at some trends in the signalling arena that may impact on the cost of train control systems in the future.

1 INTRODUCTION

KiwiRail is the State Owned Enterprise responsible forproviding, operating, maintaining and developing theNew Zealand railway network. The KiwiRail network iscomprised of approximately 4000km of track. Thenetwork is predominantly single line with crossing loopsbut more extensive infrastructure is deployed in bothAuckland and Wellington where suburban passengerservices are operated.

From a signalling perspective all KiwiRail interlockingsare either electromechanical or computer based – thereare no purely mechanical interlockings remaining inservice. Signalling systems and equipment in use rangein installation date from the mid 1920’s (AutomaticPermissive Block) through to a 2013 ETCS level 1system which is currently being commissioned inAuckland.

Cost constraints and remoteness have required NewZealand signalling engineers to become extremelyinnovative in an effort to extract as much out of existingassets as possible. Since the late 1980’s railways inNew Zealand have been under extreme pressure toreduce costs in an effort to provide long termsustainability.

2 NOTATION

ARS – Automatic Route Setting

COTS – Common Off the Shelf

CTC – Centralised Traffic Control

DLAS – Double Line Automatic Signalling

ETCS – European Train Control System

LAN – Local Area Network

NIMT – North Island Main Trunk

NTCC – Network Train Control Centre

PC – Personal Computer

SCADA – Supervisory Control and Data Acquisition

TWC –Track Warrant Control

3 ASSET MATCHED TO OPERATIONALREQUIREMENTS

During the late 1980’s and 1990’s a majorreorganisation of rail operations was undertaken acrossthe New Zealand Rail network. The result was a markedimprovement in operational efficiency and a significant

reduction in signalling and telecommunications costsprimarily as a result of:

• Poleline elimination;

• Removal of maintenance intensive mechanicalsignalling equipment;

• The associated closure of remote maintenancedepots.

This reorganisation effectively left the railway with threeprimary systems – each matched to the density of railtraffic carried.

DLAS interspersed with remote controlled interlockings

is used in suburban areas and on high density freightcorridors. These systems typically run withoutsignificant Train Control intervention and also includesome signal boxes. The recent resignalling of theAuckland suburban network has enabled the location ofall trains to be visible on a Train Control screen and allsignals to have some level of remote control.

CTC is used on medium to high density freight routes.This system is typically utilised where single linesections are separated by regularly spaced crossingloops. A level of Train Control involvement is required toschedule and signal train crossings but the system doesintegrate ARS to minimise train control workload.

TWC is used on low density freight routes. This systemrelies on a manual transaction (read and read-back)between Train Control and train drivers to provide anauthority to occupy a section of track. Train crossingsare coordinated by Train Control but, in most cases, the



IRSE Australasia Cost Effective Signalling – Sweating the Asset In New Zealand


Otiria

Whangarei

DargavilleWaiotira

Wellsford

Helensville

Mission Bush Pukekohe

Te Kuiti

Te Awamutu

Rotowaro

Hamilton

National Park

Kawerau

Murupara

Kinleith

Tauranga

Oringi

Karioi

Waipukurau

NapierHastings

Gisborne

Wairoa

Whareroa

Wanganui

Stratford

Kapuni

New Plymouth

Woodville

MastertonWaikanae

Wellington

Palmerston North

Marton

Auckland

Ngakawau

Westport

Reefton

IkamatuaRapahoe

Greymouth

HokitikaOtira

Rolleston

Christchurch

Lyttelton

Spring CreekPicton

Lake Grassmere

Kaikoura

Ashburton

Temuka

Timaru

Oamaru

Port Chalmers

Palmerston

DunedinTaieri

Balclutha

Gore

Edendale

Bluff

Invercargill

WairioOhai

Taumarunui

Track Warrant

Control

Other

Double Line

Automatic

Symbol Description

Centralised

Traffic Control

Mothballed

Single Line

Automatic

Arthur’s Pass

Stillwater

Lepperton

Vernon

Belfast

Belfast

Styx

Hornby

Junction

End of

Branch

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Woolston

Lyttelton

Station Limits

Rolleston

Christchurch Inset

Port Chalmers

Sawyers Bay

Mosgiel

Wingatui

End of Taieri

Branch

Taieri Gorge Railway Ltd

line to Middlemarch

Hillside

Dunedin Inset

ChristchurchStation Limits

CTC

DLA

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Westfield

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Papakura

Avondale

Onehunga

Morningside

Penrose

Port of Auckland

Auckland Inset

Johnsonville

Wellington

Melling

PetoneWoburn

Hutt Workshops

Gracefield

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Distant Junction

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Signalling Rules

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10-May-13

Figure 1: New Zealand Signalling Systems May 2013




setting of points to facilitate a crossing is an on-sitemanual or semi-manual process.

The current prevalence of these systems for the NewZealand rail network is shown in Figure 1. Note thatAlternative Signalling Rules (ASR) are a combination ofCTC and DLAS and will be progressively introducednationwide.

4 EQUIPMENT STRATEGIES

4.1 Reuse of Equipment

Signalling works in New Zealand tend to come in waveswith changes generally driven by changing operationalrequirements rather than signalling asset obsolescence.Signalling assets tend to have a long lifespan and as aresult there is an opportunity for some signalling assetsto be reused or cascaded to lower capacity lines whenremoved as part of signalling upgrade works.

During the mid-1980’s the central part of the NIMT was

electrified and required resignalling to provideelectrification immunisation. As a consequence anumber of points machines and relays were removedfrom service. All life expired or near life expiredsignalling assets removed from service were scrappedbut those with some remaining life were overhauled andcascaded for use in the 1990’s as part of the conversionto TWC. This mainly occurred with points machines andQ style relays but significantly reduced the cost ofproviding semi-automated motorised crossing loops inTWC territory.

4.2 Equipment Overhaul and Refurbishment

As mentioned in the previous section signallingequipment generally has a long lifespan. However, aswith all mechanical devices, the equipment willeventually reach a stage where the required level ofservice is not able to be provided.

Over the years KiwiRail has had success with overhaulprogrammes on points machines, barrier mechanismsand relays.

Under a regular refurbishment policy Westinghouse M5points machines installed in Wellington in the 1930’swere able to remain in service until 2010.Refurbishment of points machines involves:

•

A full strip down of the machine• All cast components cleaned and repainted

(two pot epoxy)

• All machined components fine blasted andclear coated

• New detection and lock slides

• Complete rewire

• Motor reconditioning including coils andarmature dried and then resin varnish filled

• Full testing

Figure 2: GRS Machine Prior to Refurbishment

Figure 3: GRS Machine Post Refurbishment

Typically the overhaul costs around 30% of the price ofa new machine and will allow around 20 years ofcontinued operation.

Similarly KiwiRail have instituted a programme of barriermechanism overhaul. A barrier overhaul includes:

• A full strip down of the mechanism

• External casing blasted and painted

• All internal components cleaned and checked.Worn parts replaced

• Complete rewire and upgrade to contemporarystandards where required (e.g. Kyosanmechanisms fitted with Q style contactors)

• Motor reconditioning including replacement ofbearings and seals, commutator turn down,brush replacement

• Full testing

This overhaul programme in combination with aprogramme to retrofit electromagnetic brakes hassignificantly reduced the cost of barrier mechanismrenewals. Similarly to point machines the overhauledcost is around 30% that of a new mechanism with an

expected service life of 20 years.




Figure 4: Barrier Mechanism Prior to Refurbishment

Figure 5: Barrier Mechanism Post Refurbishment

5 COMMON OFF THE SHELF EQUIPMENT

Due to high safety standards and a relatively smallmarket bespoke railway signalling equipment does havea high cost. Wherever possible KiwiRail will look to useindustrially hardened non-railway specific equipment tominimise cost. Two examples of this are KiwiRail’scentralised train control system and recentexperimentation with road traffic technology for levelcrossings in yards and terminals.

5.1 KiwiRail Train Control

In the late 1990’s a project was undertaken to centraliseall of the New Zealand Railway train control operationsinto a single centre. At the time there were seven traincontrol offices spread throughout the country.

In the years prior to this project several proposals toundertake the centralisation using railway controlsystems available at the time were prepared – each timethese proposals foundered because the cost wasprohibitive. By the mid 1990’s the use of standardpersonal computers for control of utility networks (eg.

Power, water, pipelines) was becoming prevalentprompting KiwiRail to investigate the suitability of thesesystems to control railway signalling.

As a result of this Realflex ® was selected as thesignalling control platform for KiwiRail’s NTCC

[1]. By

the time this project was completed in 2000 the overallcost was around 10% of that provided in previousproposals using bespoke railway signalling controlsystems.

Although this system is not as feature rich as adedicated train control system it does have sufficientfunctionality for a predominately single line freightrailway like KiwiRail.

5.1.1 System Architecture

One of the advantages of using COTS products is thatthe development cycle is relatively short and evolution inline with technology trends occurs. Since the initialdeployment of Realflex ® the architecture has altered tothe point where the system is now comprised of thefollowing:

• Main and Hot Standby servers running onserver grade hardware and the QNX operatingsystem.

• Each control desk is equipped with a standardPC running Microsoft Windows (current XP orWindows 7). Each PC is running up to 4screens.

• A 1GB Ethernet LAN backbone betweenservers and the main network switches.

• Dual 100Mb Ethernet LAN between networkswitches and control desk workstations.

5.1.2 System Configuration

The core of the Realflex ® system is a database which isconfigured to uniquely identify each required point(control, indication or virtual). This database determinesthe colour associated with each state of each point andthe addressing details for each point which is thenpicked up by the communications driver responsible forcommunicating with the remote field devices.

Figure 6: Realflex ® Database Point Configuration




Operator screens are designed in two layers – static anddynamic. The static layer is used to define the basicscreen layout (track diagram). In the dynamic layeranimation of the static portions are provided (e.g. tracksection status) by linking the static portion to a databasepoint.

Figure 7: Realflex ® Dynamic Layer

Figure 8: Realflex ® Operator Zoom Screen

Changes to both the database and operator screens canbe undertaken “on-line” without the need to restart the

system.Realflex includes a scripting tool which can be used toadd a level of functionality and automation to the basicsystem. Although this tool is not suitable for complextasks (eg train describer) is has been used extensivelyto create the following:

• Automation of regularly used train movements(e.g. crossings). Allowing these moves to beactivated by the Train Controller with a singleaction from where the system will monitor thelocation of trains and then set routesaccordingly.

• The provision of non-vital blocking to prevent

signals being called to clear into a section oftrack if the section has been blocked.

• Full automation of a 12km section of single linepassenger only line including 3 crossing loops.

5.2 Freight Terminal Level Crossing System

5.2.1 The Problem

In 2012 a new freight forwarding facility was built inPalmerston North Yard. This facility is serviced by railbut also requires frequent truck access via a one waysystem which crosses the rail (two tracks) in two

separate locations.

Figure 9: Palmerston North Yard Level Crossing Layout

5.2.2 The Solution

As the site requires integration between traffic controland level crossings it was determined that a traffic lightsolution would be the most suitable and cost effective.

The requirements for the solution were:

• Train movements are announced by a shuntingstaff activating a trackside pushbutton.

• Once a train has passed over the level crossingthe “train” phase must automatically cancel.

• Train movements are authorised across thecrossing by a signal that confirms that roadtraffic has been stopped.

• Vehicle movements have normal right of way.

Traffic Design Group were engaged to design a solutionand came up with the following:

Train detection achieved via inductive loops. As well asproviding automatic cancelling following a trainmovement these also automatically trigger a “train”phase if a train is detected travelling towards thecrossing and the phase has not been activated bypushbutton

Traffic lights at each crossing showing:

• Solid red visible to road users for traffic stop.

•

Solid amber visible to road users for “train”phase activated stop if you can safely.

• Solid green visible to road users for trafficproceed.

• Red “T” visible to rail users for train stop.

• Green “T” visible to rail users for train proceed – Note that this is to be changed to a white “T”light after initial evaluation.

As well as being cost effective (Around 30% of the costof a conventional signalling based solution) this solutionallowed seamless integration with the road controlsystem and has resulted in a very effective traffic control

and protection system.




Figure 10: Yard Level Crossing – Road Control

Figure 11: Yard Level Crossing – Rail Control

6 USE OF TECHNOLOGY TO REDUCE COSTS

Railway engineers and in particular signalling engineershave traditionally been very good at identifying andadopting new technologies. There are many examplesof new technologies being deployed to provide bothinitial and life-cycle equipment costs. Within KiwiRail

examples of this include the deployment of LED signals,and remote monitoring.

LED signals are used throughout the KiwiRail networkand there is an active programme to firstly replace allincandescent searchlight signals and ultimately allincandescent multi-aspect signals with LED multi-aspectsignals. As well as providing an enhanced light outputLED signals require significantly less maintenance thanthe incandescent signals they are replacing. Thisreduced maintenance results in reduced maintenancecosts which very quickly outweigh the higher installedcost of an LED signal head.

KiwiRail is also undertaking a nationwide rollout ofremote monitors at level crossings. These monitorshave been developed by KiwiRail in conjunction withHarvest Electronics and were initially deployed tomonitor mains power outages at remote level crossings.

As well as monitoring the mains power the Harvestdevice monitors and records:

• Busbar voltage

• Half battery voltage

• Lamp current

• Bell current

• Alarm operating time

• Control system states (eg approach tracks,stick relays)

Figure 12: Web View of Level Crossing Monitor Data

The level crossing monitor effectively provides 24 hourmonitoring of the installation. Any events requiringattention are forwarded to the KiwiRail 24x7maintenance centre for attention. The data for each siteis accessible via a web browser interface and isregularly used when alarm mis-operation allegations arereceived. These monitors have already allowed regulartesting of alarms by track staff to be eliminated and asexperience with the units is gained it is anticipated thatsignals staff checking of the installation will be reducedfrom monthly to quarterly.

7 CONSIDERATIONS

7.1 Installed v Life-cycle – what is “CostEffective”

There is always a healthy tension between projectengineers (get it in and working as fast and as cheap aspossible) and maintenance engineers (once it iscommissioned it shouldn’t require special attention) withsignalling equipment. The temptation to minimiseinstalled cost is compelling but overall the railway isbetter off if the full life-cycle cost of the equipment(installation, maintenance, faults, refurbishment anddisposal) is considered. In most cases the marginal costpremium required to secure reliable, low maintenance

equipment is defendable, however, as mentioned insection 3 it is still important to match the installedequipment to operational requirements. In many lowdensity lines the impact of failure may be such that a




higher failure rate can be tolerated and less robust (andless expensive) equipment installed.

7.2 Asset Obsolescence

KiwiRail have an asset policy of renewing “like-for-like”in most cases to life extend an installation by replacingelements or components with full scale upgrades onlybeing triggered by changing operational requirements.In most cases this is viable but eventually the assetreaches a stage where parts of it become obsolete andupgrades to modern equivalent equipment is required.

An example of this has been historically with shelfmounted relays. Over the years KiwiRail have replaceda number of shelf mounted relays with Q style relaysmounted inside a shelf conversion frame. This hasallowed in-situ partial upgrades without the need toundertake extensive rewiring.

There is a potential looming issue with Q style relays.Many of these have now been in service for excess of40 years. Most are still operating reliably but KiwiRail

has a policy of an in-situ visual inspection of Q relays(rather than age or usage based replacement) whichmeans that some failure modes may not be detected. Inorder to understand the potential issues better KiwiRailhave invested in a number of automated relay test setswhich are being used to sample test plug in relaysthroughout the network. The results of this testing willinform an asset strategy for plug in relays.

7.3 System Risk

Another issue with a like-for-like replacement strategy isthat the underlying system design does not generally get

changed. In KiwiRail’s case most of the remainingsignalling systems were deployed since the 1960’s andbecause of this generally comply with contemporarysignalling practice. However there are some systemswhich were deployed earlier - for example the MidlandLine signalling system which runs across the SouthIsland from Rolleston to Greymouth.

The Midland Line was signalled in the late 1920’s with aSingle Line Automatic Permissive Block system. Overthe years most parts of this system have been renewedbut, apart from a few minor tweaks, the underlyingsystem and associated principles are still in daily use.This system has now reached the stage where it isextremely difficult to integrate with a contemporary

railway operation and either an extensive upgrade or fullreplacement is required.

8 TRENDS

8.1 Refurbishment and Maintenance of OldEquipment

As society has moved more towards instant gratificationit seems that the skillsets required to refurbish andmaintain old equipment are on the decline. It is difficultto attract new personnel into roles that require extremeaccuracy, mechanical dexterity and patience – all of

which are essential for the refurbishment of signallingequipment.

In addition to the personnel skillsets it can be difficult toobtain replacement components for some equipment. In

many cases spare parts are no longer available fromequipment manufacturers so the only alternative is toeither pillage from out of use equipment, find readilyavailable equivalent components or manufacture fromscratch.

KiwiRail is still training new resources in this area but isalso implementing asset strategies that will ultimatelysee all shelf mount relays removed from service. Theprioritisation for this strategy considers factors like assetpopulation, complexity and replacement alternatives.

8.2 Equipment Lifecycle

Since the 1970’s railway signalling equipment has beenmoving from electromechanical to electronic platforms.Electromechanical devices and early discretecomponent electronic equipment can be kept going withspare parts – in most cases modern equivalentcomponents are available. However more modernequipment comprised of integrated circuits is moredifficult to maintain and repair.

In KiwiRail an example of this is that a mid 1980’sWestinghouse S2 CTC system is likely to be replacedbefore an early 1970’s Westinghouse F1 CTC system.Adequate spare parts are available for the F1 systemand many of the cards can be repaired with readilyavailable electronic components whereas the integratedcircuits used in the S2 system have long since ceasedproduction.

Almost all new installations are microprocessor basedand because of this an asset strategy of like-for-likerenewals for this equipment is not appropriate. On theflip side modern equipment utilising industry standardequipment and protocols should get cheaper over time

thereby reducing installed costs. For KiwiRail it remainsto be seen if the combination of reduced installed cost,reduced maintenance cost and more frequent assetreplacement will result in lower life-cycle costs thantraditionally more expensive equipment that has a longeroverall asset life.

8.3 Communications Based Signalling

Communications based signalling allows the removal oflineside equipment but replaces it with train-borneequipment and extensive communications networks.Traditionally the drive towards in-cab signalling hasbeen provided by either high speed or the need for

higher capacity than can be provided by linesidesignalling. As the cost of communications basedsignalling systems decreases the opportunity does existto significantly reduce signalling infrastructure costs onlow to medium density lines by eliminating linesidesignals and track based train detection.

9 CONCLUSION

The perceived high cost of signalling equipment andsystems has, is and most likely always will be a burdenthat signalling engineers have to bear. Although a largeproportion of the cost of signalling equipment is due to

the required safety levels and robustness there are stillopportunities to ensure that the overall cost of signallingsystems are minimised.




Since the 1980’s the New Zealand railway network hashad limited funds available for investment. This hasrequired innovation and ingenuity from signallingengineers to make the most of available resources toensure a safe operating railway.

The initial response to cutting costs commenced in thelate 1980’s when TWC was deployed on low densitylines. As well as significantly reducing operatingpersonnel costs the amount of signalling asset was alsoreduced – thereby slashing maintenance and renewalcosts. Matching signalling systems to operational needsis a key component of optimising costs.

Due to isolation KiwiRail has become very adept atrefurbishing and reusing signalling equipment. Overallthe asset life extension gained by refurbishingequipment – particularly relays, points machines andbarrier mechanisms is valuable and another keycomponent of optimising costs.

KiwiRail have also successfully reduced costs by takingopportunities to use COTS equipment. This is difficult inareas requiring high levels of safety but has been

successfully utilised for KiwiRail’s centralised traincontrol system. The use of standard traffic control andsignalling equipment has also recently been used forlevel crossing and traffic control in Palmerston Northyard.

While it is important to ensure that signalling costs areminimised a focus entirely on installed cost for signallingequipment and systems can be misleading – particularlyif ongoing maintenance and renewals costs are notconsidered. It is also important to note that eventuallycontinued equipment overhaul and like-for-like renewalhas an end point due to a combination of equipmentobsolescence and overall system performance (bothreliability and safety).

As technology is changing it is obvious that equipmentlife cycles are getting shorter and that the electronicsystems currently being installed will have a shorterlifespan than the electromechanical systems they arereplacing. This does provide the opportunity of regulartechnology refresh and is balanced by the overallsystem life-cycle costs being similar but is an importantconsideration in asset planning and management whichcan easily be overlooked.

10 REFERENCES

[1] Skilton, J T Tranz Rail’s National Control Centre,IRSE Australasian Technical Meeting, July 1998

11 ACKNOWLEDGEMENTS

The author acknowledges the support and permission ofKiwiRail to publish this paper.

AUTHOR

John Skilton

CPEng, BE (Elect) Hons, MIPENZ, FIRSE

KiwiRail Infrastructure and Engineering

John Skilton is a Chartered Professional Engineer andmember of IPENZ with twenty years of experience inrailway signalling, telecommunications and controlsystems.

John graduated from the University of Canterbury withan honours degree in electrical and electronicengineering in 1991. Since then he has worked in anumber of roles within the New Zealand rail industry witha focus on signalling and telecommunications systems.John was instrumental in developing the system utilisedto control signalling from KiwiRail’s train control centreand headed the project to consolidate operations intothe centre. John has been closely involved withresignalling projects on both the Auckland andWellington suburban networks as well as settingstandards for the New Zealand rail network.

John recently moved to a new position to manage the

KiwiRail’s Infrastructure and Engineering Central Regionwhich covers engineering maintenance of all disciplinesin the bottom half of the North Island and isheadquartered in Wellington.

irse australasia launceston july 2013 - john skilton - cost effective signalling

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