project ‘tractor’ sound fx - south west digital · how to install ‘plug and play’ dcc sound...
TRANSCRIPT
42Modern Railway Modelling | Summer 2005
‘TRACTOR’ SOUND FXHow to install ‘plug and play’ DCC sound to recreate ‘Tractor’ thrash. Photography MRM Studio.
PROJECT
It’s an early start, an early diagram and
you discover that your train has a Class 37
allocated to it. Collecting your kit bag and
pulling on your high visibility vest, you wander
out from the bothy into the early morning mist
and over to your assigned locomotive. After the
usual checks, it is time to start the engine and
leave it to warm up for about ten minutes or
so. The whine of the starter motor is followed by
the reassuring firing of the English Electric diesel
which chugs away amidst clouds of clag from
the cold exhaust ports. After a short time, the
engine settles down as it warms through and the
exhaust thins out. Compressors are running and
air pressure is up. Time to ease the brakes off
and move the locomotive off the stabling point.
Another day, another diagram, another train.
However the difference here is you are at
home, in your railway room and with a DCC
throttle in your hand. For with DCC and Lok
Sound, to start your Class 37, leave it to warm
up and then move it off with full and authentic
sound including the release of the brakes has
to be one of the most exciting developments
for UK outline modelling since DCC first
appeared. Strictly speaking, it is not new to
overseas modellers because Roco has offered
models with installed sound for a while now
whilst Kato makes provision for speakers in its
new HO scale models.
However, the Class 37 sound recordings in
Lok Sound decoders is a UK first for the Class,
made possible by the efforts of Steve Weeks
at South West Digital. There was a hiatus in
availability as Lok Sound released its Lok
Sound 3 decoder and then delayed with the
programmer. Since November 2004, this has
been resolved and Lok Sound with Class 37
sounds is available by mail order once again.
The quality of speakers has improved too
and a variety are now available in different
shapes and sizes for Lok Sound decoders
including a fairly beefy 20 x 40mm oblong one
which will fit in a Bachmann Class 37. Perhaps
the two barriers to the onward development of
sound for UK outline diesels is cost (the South
West Digital programmed Lok Sound decoders
will more than treble the value of your average
RTR loco) and that the producers of UK outline
models, such as Bachmann, are filling its
products with so much metal that there is barely
room for a normal mobile decoder, never mind
speakers. The Bachmann Class 20 is a case in
point.
Nonetheless, the Bachmann Class 37 is a
good choice and this project shows how to
install both decoder and speaker into the latest
version; the Class 37/0. As you will discover the
actual installation from an electronics point
of view is very simple. Less straightforward is
ensuring that sufficient room is available inside
the model to allow the free operation of both
decoder and speaker. The Lok Sound decoder
is supplied with a 23mm diameter speaker
which would, under normal circumstances
be adequate for the job. However with a little
modification to the bodyshell it is possible to
fit the larger 20mm x 40mm oblong speaker
into the boiler compartment end and gain the
benefits of better sound as a result.
Only simple tools are required to complete this
project including tweezers, pliers, insulation tape,
double-sided adhesive tape, a sharp scalpel and
soldering iron. A soldering iron is only needed if
you intend to replace the round speaker with the
larger oblong version – the original should be
unsoldered from the two decoder leads and the
new one soldered in its place.
The same rules apply to the fitting of sound
decoders as they do to conventional mobile
decoders. Be sure not to place any pressure on
any component when re-fitting the body, do not
let any part of the decoder come into contact
with metal and do not wrap the decoder in
insulation tape. Always test the installation of a
decoder on a programming track by obtaining
an address read out on CV1 before placing
the model on your layout and exposing it to
full power. Programming power is sufficient to
detect any fault in the model without running
the risk of damaging the decoder. It is also
worth noting that the model should be in good
running order and any servicing completed
before a decoder is installed.
The photographs on the next two pages
demonstrate the installation process.
OperationOperation is about as close to real driving as
is possible in 1:76 scale. Assuming your model
is stationary, you can thumb function button
F1. Remember, your running lights are still
controlled by F0. The model ‘starts up’ and then
idles until you open up the throttle (in whatever
manner your hand-throttle works). The brakes
will release and the model will move away
with the appropriate engine power sounding
through the body. When bringing the model
to a stand, the action is accompanied by the
squeal of brakes and the return to idling.
Other functions are used for other sounds:
functions F2 to F4 are for a variety of horn
sounds. F5 offers a shunting mode which is
quite effective. Function mapping can be used
to allocate other lighting effects to function
buttons F7 and F8.
In all, to hear a Bachmann Class 37 move
away with the classic English Electric engine
sounds and exhaust beat is quite an experience.
To simply ‘drive’ the locomotive with sound is
fun. It makes you think about correct operation
and that is fun in its own right.
Engines idling, EWS Class 37/4s return from the Far North with a train of Safeway intermodal boxes and loaded VGA/VKA vans. Normally a Class 66 diagram, 37 406 and 427 do the honours on November 1, 2004. Photographed at Clachnaharry, the sound of both locomotives powering up after the 10mph PSR at this location was impressive, as always. This can be done in 4mm scale with Lok Sound 3 decoders and programming by South West Digital. Brake squeal and basic horn sounds are all programmed into the decoder.
42-45-noisy tractors.indd 42 11/4/05 9:35:09 am