This is the second of a series of articles describing the progress of the project.
The use of "now" and "the present" refer to 2003.
The raised track signalling project continues to make slow but steady progress. There is
admittedly not a lot to see on the ground yet, which is not surprising considering the hot, dry
summer we have just endured - hardly the right weather for digging holes! However the
design of the system is complete, and virtually all of the materials have now been procured.
We now know the final cost of the project, which will be around £2000.
A test set-up has been built to prove the logic of the system, thanks to Tony Vereker, using
actual components that will be used in the final product. This revealed a flaw in our logic,
which would have meant that we could only get a maximum of two trains into the station at
any one time. We decided that with five trains in operation, we need to be able to get at least
three of them into the station and this prompted a major re-think, which took some time to
resolve. Suffice to say that after many hours spent at the computer by yours truly, the signal
and cable route layouts, block diagram, schematic diagram, and bills of materials have all
been fully revamped, and we are now fairly confident that we have got it right.
Our first job was to lay in a steel pipe across the centre of the picnic area, or the "corral" as it
is known. This will carry one of three arterial cable routes from the control panel, which will
be situated under the footbridge. The steel pipe is actually a series of scaffold poles coupled
together and buried about 100mm deep, its purpose being to protect the cables from the tent
pegs that get driven in from time to time.
The signal posts, made from scaffold poles, steel plates and angles, are now occupying my
garage where they are being welded up! A total of seven posts will be installed, of which five
are "singles" and two are "doubles". One of the "doubles" is shared between the raised and
ground level tracks, with a head for each. We decided to fit this one first and wire up the
ground level head, so that this phase of the work could be finished in time for the rally. The
end result is that ground level trains no longer have to wait at a red signal behind the
carriage shed when the diamond crossing is in use, but are instead held at the front of the
carriage shed where the driver has a view of what is going on. The semaphore arm has
been removed from the side of the carriage shed, as it was redundant anyway. The old
colour light signal has been retained at the rear of the carriage shed, but this is now wired as
a "distant" only and as such is capable of giving only a yellow or a green aspect.
Having completed this phase, we have now returned to the raised track, and by the time you
read this a few more signals will have appeared. Each signal post is set into a concrete base
of 400mm diameter by 450mm deep, and I defy anyone to kick them over! Our plan is to dig
the cable trenches and cable up each signal as we go, so that the grass can recover and we
do not have to return to re-dig an area that has already been dug up.
Our first trial with one of the Parkside signal heads was on New Year's Day and we were
surprised at the brightness, bearing in mind that the lamps are only 2.2W torch bulbs. Since
then we have seen what they look like on a bright summers day, and it has to be said that
the brightness is disappointing in these conditions. We have improved matters slightly by
changing to 3W bulbs, but I think that some more experimentation will be needed before we
are satisfied.
If anyone feels like joining in the fun on Saturday afternoons, Tony and I will be very pleased
to see you. The pay is nothing an hour, but the tea is free!
On to Part three
Back to Signals menu
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