That would be great to have some references! Also eventually to all other cool stuff you implemented :-)
Vladki, do you have access to the github? Can you "do" stuff there?
Hi, my git access seems to work. I'm now trying to play with the new signalling. I would like to implement the modern circuit-block/in-cab signalling, with the current graphics for light signals (white rim, black background). The signals would be:
- 2-aspect signal = 2 lights (red, green)
- 2-aspect presignal = 3-lights (green, white) - should be blinking
- 3-aspect signal = 4 lights (red, 2x green - caution, green+white - clear) - the bottom light should be blinking, but we cannot do that now. Any ideas how to distinguish them?
- 3-aspect choose signal = 5 lights (red, green+white - clear without choose, 2x green - clear with choose (non-bilnk) / caution without choose (blink), 3x green - caution with choose)
maybe also:
- 2-aspect choose signal = 3 lights (red, green (without choose) , 2x green (with choose))
Similar aspects could be for absolute block signals (semaphore and light signals), just without the 3-aspect 4-light signal. And 3-aspect choose signal would show clear with one green light/arm.
Dwarf signals as they were plus one more for end-of-signalling with diagonally placed lights
Do you have some evidence about using token block signalling in sweden and the related signals?
BTW James, I have a lot of questions about the new signalling. Where is the proper place to discuss it?
Well I have to get the questions and comments out of my mind.
<long stuff here>
I cannot resist comparing british and czecho-slovak (or even austro-hungarian and neighboring) signaling.
- permissive signals - we have those - modern circuit block signals on plain track that have the pole painted white are permissive. Those with red/white striped pole are absolute. But I think the reasoning behind was not to improve throughput, but to avoid blocking the whole line if one signal gets broken. At times there was a label on signals in uphill sections that allowed heavy cargo trains to pass slowly on danger without stopping (as they would struggle to start moving again.
- call on - we have a special aspect on signals within the reach of station (entry, exit) to allow trains enter the station if signalling is somehow broken, or if the train has to enter an occupied track. So this is different. There's no special aspect on perrmisive signals on plain track. It is only on otherwise absolute stop signals.
- absolute block signalling. I was looking for the closest equivalent here - it is old telephone signalling and half-automatic electromechanic signalling. The signalman had to communicate in similar way to their british colleagues:
A: I've a train for you
B: ok, let it in
A: there it goes
...
B: it passed through (complete)
and so on.
However there is one significant difference. Czech signalling distinguishes signalboxes at stations (where trains can pass each other), and intermediate boxes on plain track. This is important for operation on single, bidirectional track. The start of communication goes on between stations, with intermediates only listening and acknowledging that they have reserved their block accordingly. When the train passes the intermediate box, a next train can follow in the same direction. When there are trains for the other direction, the station signalmen have to agree on changing the direction (and wait for the track to clear of course). So I think the "blue" reservations described for circuit block, should be available for absolute block as well. However I have tried how it works, and I see that if there is only one intermediate signal box, then the whole path is reserved, which works just as expected. More then one could make deadlock, but that may be a design decision.
Another thought is about reservations. In real life all reservations go from one signal to another. If there are train stops in between (without track junctions), then the track is reserved through them. The train continues according to the last signal seen. Not in drive-by-sight. And the whole stretch of track remains reservered unitl the trains leaves the block completely. So I think that:
a) the reservation should go through any platforms and stops until the next signal
b) trains should be forbidden to turn around on platforms without signals (except for dead end tracks)
This will reduce the need for long/token-block signals on bidirectional tracks
Tokens and staff. I think there should be some indication where is the staff (in cabinet or not), or if a token can be released or not. Perhaps also if the train is in possesion of staff/token. Max_speed of staff cabinet or token box should be (almost) zero. The driver has to stop, and go for the staff/token. Also the token should be returned at box for opposite direction. After returning the token, the train should continue in drive by sight, if there is no other signal. Thus bidirections staff/token box makes sense - return one token and take another for the next section.
I think that the previously discussed T semaphores could have been used in combination with tokens/staff. While the staff/token secured the track between stations, the T semaphore (with entry signs), protected the station, allowing for shunting while there was a train on the track approaching the station. Their position and shape was IMHO just to save on installation costs and to keep is as simple as possible. Later the entry signs would be replaced by entry signals operated by wires or electricity. But the token would not be returned at the entry (choose) signal, but at the station.
