Signalling
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Colour Light Signalling
The diagram above shows what we hope to eventually have fitted. The letter code makes reference to the control box - CH Compost Heap, HO Houchel (neighbours name) RS Romford South Box. RS signals will be manually controlled by a 10 lever frame in the signal box.
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After early trials with treadle switches
the decision was made to revert back to using track
circuiting as trialled in the tunnel. Originally I used
connector blocks to connect all the components together
but this was a bit messy. Left - One of the original control box under the bridge. These components were removed and replaced with our new modular system. |
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Above - Our new boards
which we are using on all our automatic signals. The
relay at the bottom right is to control the points and
crossing set up. Left - The same box with the new relay boards in place. By using individual boards for each section, if one fails it can be easily replaced. |
Track sectioning. Previously we used paxolin board to hold the rails but we have found it was quite hard to keep the rails inline. As an alternative we have used delrin blocks which has a groove machined in the top edge which holds the rails in line.
Below right - Having cleaned up and greased a fishplates to allow a bit more thermal movement, we found that the grease stopped the flow of electricity between the two rails. To extend the circuit we have to loop around the join, just as they do on the real thing.
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Initial Problems
While using 12v for the track circuits we have come across a few problems.
1st few trains tend not to give good contact - presumably this is down to rust.
Wet steel rail track can hold the circuit open. For some reason the steel seems to let the electricity carry better betweent the rails. Presumably the current runs down the track screws and through the sleeper. It doesn't let enough through to trip a circuit but it does let enough through to hold a relay open once a train has set it. We have cured this by adding a load between the switched live rail and neutral.
Temporarily we are using a car battery to run the signals off. If the battery starts to drop the voltage the circuits fail to detect the trains. Eventally they will be powered from a fixed power supply so this shouldn't be a problem.
Lever Frame
Initially we started on construction of a 2/3rd scale lever frame but it soon became apparent that no signal man would be able to change the levers quick enough for the amount of trains we run on one of our open days. It also was complicated to get interlocking working so we went back to the drawing board and came up with the Westinghouse Frame copy..
The frame controls signals up the left side of the garden as well as levers 1-4 having over ride of some of the automatic signals.
I had intended to keep the wiring tidy under the frame but I soon became swamped.
23 live wires from the indicator lamps on the rear panel
24 live wires from the lever microswitches
5 main relays + 1 spare. -
Lever one override for inner track tunnel signal
Lever three override for outer track tunnel signal
Signal 11/12 - feathers
Signal 11/12 - on off
Reverses polarity for changing points
Relay board bottom right in picture is a track circuit just after signal 11/12. This latches the signal to red which can only be reset by returing the lever back to red. This can be switched off if the signal man needs to leave the box.
