I model the Great Northern in rural Minnesota during the 1950's.
I have 3 questions on ABS signals and double track crossovers.
1.Are there any good online resources on ABS signaling, especially pertaining to model railroading setups?
2.With an ABS signal system, how would you signal the crossover below?
3.Do double track crossovers happen in small towns prototypically or would this be a rare thing? I am doing it out of space constraints, but most crossovers that I have seen happen on the outskirts of town or in rural areas.
Since I am having trouble adding images here is a diagram of what I intend to do on my 2 x 7 HO module.
TOWN
______industrial siding_______
/ \
<<<____________________________________westbound
⁄
eastbound____________________________________>>>
DEPOT
I like some of the information presented here:
http://www.lundsten.dk/us_signaling/
Look at the first two basics sections first. You can customize from there.
There are other signal sites out there but this one came to mind... have fun!
Ed
The simplest would be to have one eastbound signal east of the depot and one westbound signal west of the west turnout of the industrial siding. In ABS territory the crossovers should always be lined straight through. If they are to be used the train will have orders allowing it to use the opposing main, and will be stopping so the head-end brakeman can throw the crossovers by hand. The tail end would then return to switches to the normal position once the train has cleared.
The reason for placing the signals beyond the depot is so trains delayed in the block (making a station stop) or returning to the normal route, are given a signal indication allowing them to proceed at track speed.
Note that signals are not usually provided for trains running against the current of traffic (wrong main).
Smurphy 1.Are there any good online resources on ABS signaling, especially pertaining to model railroading setups?
There are resources on how the signal systems operated, very few on how the signals were placed.
Based on the track profiles of the double track ABS I've seen, I wouldn't. No real need.
Crossovers happen where railroads need them. Your crossover would be rare, since its a facing point crossover, the majority of crossovers in double track are trailing point crossovers. Its safer.
the crossover would most likely be a trailing point one, and the signals beyond the points to give trains going through the crossover a favorable signal leaving the crossover. You wouldn't want the signal right up next to the crossover because it wouldn't speed up the trains. Crossovers in DT-ABS are typically 10 mph crossovers and since the switches are manual the train has to stop and line the switches behind. That means that the train will be "delayed in block" and has to operate at a reduced speed until they can see the next signal. If the signals are 2-3 miles apart and the signal is right up at the crossover that means the the train has to run for about 1.5-2.5 miles at reduced speed to see the next signal. If the signal is 1 trainlength beyond the crossover, the train has to operate at reduced speed only as long as it takes to get through the croosover and see the next signal.
You also have to remember that to a train dispatcher and the signal system the "industrial siding" is irrelevant. The only thing that is tied into the signals system are the switches and they are set that if the switch is open the signal before the switch drops to red. That signal could be near the switch or 5 miles away.
Since I am having trouble adding images here is a diagram of what I intend to do on my 2 x 7 HO module. TOWN ______industrial siding_______ / \ <<<____________________________________westbound ⁄ eastbound____________________________________>>> DEPOT
If I was going to add a signal, I would add a train order signal at the depot.
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Dave H. Painted side goes up. My website : wnbranch.com
dehusman Crossovers happen where railroads need them. Your crossover would be rare, since its a facing point crossover, the majority of crossovers in double track are trailing point crossovers. Its safer. the crossover would most likely be a trailing point one, and the signals beyond the points to give trains going through the crossover a favorable signal leaving the crossover. You wouldn't want the signal right up next to the crossover because it wouldn't speed up the trains. Crossovers in DT-ABS are typically 10 mph crossovers and since the switches are manual the train has to stop and line the switches behind. That means that the train will be "delayed in block" and has to operate at a reduced speed until they can see the next signal. If the signals are 2-3 miles apart and the signal is right up at the crossover that means the the train has to run for about 1.5-2.5 miles at reduced speed to see the next signal. If the signal is 1 trainlength beyond the crossover, the train has to operate at reduced speed only as long as it takes to get through the croosover and see the next signal.
I agree with placing the signal one train length beyond the switch.
However, to be technical, a train crossing back over to run with the current of traffic ABS is "Entering the block between signals" at the crossover. This would require running restricted speed until the leading wheels pass the next block signal. Even if that signal is seen to display a proceed indication when coming up to it.
Jeff
Thanks for the tips everyone, I really appreciate it! The crossover was in fact a facing point on the prototype but took place about a mile east of the town.
This question begs another. Is anyone aware of a Swift T.O. Signal available in HO scale either functional or non-functional?