Passing AI trains on single lines without signals

[mazda]

Dear all

Last month there was a question about whether you could set up crosses on unsignalled single lines. The Tallylyn was the railway in question. The verdict was that it was basically impossible.

This is just a thought on what might work and I might try it tonight (too excited by the possibilities to wait before posting!).

Why not set up all paths for left hand running through the loops and place double reverse points just before the exit points from the loop.

The theory is that any train (player or AI) will only have a path projecting forward to the next loop and setting the path through the points and into its side of the loop - but no further. An opposing train in the next section will have a path doing the same thing from the opposite direction. Once safely in their respective sides of the loop both trains hit their reverse points and their paths project forward for the next section. Do this for every loop and, even if you don't know precisely where the opposing trains are, you should be able to see from the state of the points whether you have opposing traffic. A sort of virtual token system.

Without the double reverse points opposing traffic just sits outside the loop because your player train path has already set the points for your path.

Perhaps someone has already tried this, but perhaps not. It just might work!

cheers

Greg

[kevarc]

I don't think it will work. Without signals, it is a matter of timing. Reverse points only work inconjunction with signals.

[MartinH]

As far as I know the double reverse point only works with signals (it is a useful means of forcing a red signal). I haven't written any activities for the Talyllyn for a year or more, but I did manage to pass trains without too much of a problem. In fact I seem to recall a return activity with a pass in each direction.

The Swanage route is currently unsignalled (hopefully not for long), so I'll try out a few activities this weekend.

Martin

[mazda]

... Oh well, I guess the proof will be in the proverbial pudding!

I know that reverse points are usually used to force the signalling to do somethng, but they do also set the points. Note how when you trigger double reverse points you usually have to stop and start again to get a signal to clear, yet the path gets set (provided there is no conflict) even if the signal doesn't clear (watch the track monitor). So I can't see any reason why they shouldn't work on unsignalled lines. A path is just a path and the problem with an unsignalled line is that there is nothing to stop your path projecting forward to the end point, thereby tying up the entire route.

Anyway, back to work and I'll have a play on the Tallylyn when I get home tonight (its only 10 in the morning here - thought about all this while walking into work!).

Cheers

Greg

[ebensoussan]

Hi,

I have the same opinion than Kevin. I realized an activity for La Mure unsignalled single line where I have to use timing tricks such as holding the AI train in a station (you have to increase the number of passengers on the platform) and "compelling" the player to arrive in time at this station. Anyway, you have to run a lot of tests to be sure of the good timing.

[mazda]

... well, here's what I found. I set up an activity on the Tallylyn as I described in the original post - using left hand through all loops and double reverse points just before the exit points for all loops for player and AI paths.

I had two opposing trains coming towards me after leaving Wharf. Met the first one at Pendre and it stopped outside the loop. I needed to reverse a foot and then on it came for the cross. The second train stopped outside Abergwynolyn (or however you spell it) while I was still several loops away. Sat there until I got there and did my little reversal dance and then it too went on its way. So, not perfect but I did manage to cross two AI trains on a single track without signals. When I tried this before without double reverses I could NEVER get the AI train to enter the loop.

One complication on the Tallylyn is that a number of loops have track nodes half-way down their length. Double reverses don't work properly if a train is straddling a node so I placed one reverse point either side of the node. Whether this had anything to do with the Aber... problem - who knows. The first train certainly didn't mind.

Hope the above is of interest and others have a go on other routes.

Cheers

Greg

[mazda]

... - the whole point about the above is that I didn't have to muck around with anything special with timing - just set up the services and the crosses looked after themselves. No collisions, no stalemates. That's the plesaing thing about it.

Greg

[saddletank]

Excellent news. Do you plan to upload these Talyllyn activities when you are happy with them, or is this just a learning process taking you on to better things?

[mazda]

G'day Martin

Hadn't really thought about it but if I can find my ftp thingo I might do so!
Cheers

greg