I am in the process of wiring a 7’x9’ loop for automatic running of 2 (or more) trains. I will be using relays triggered by insulated outer rails to control the trains. I understand the wiring aspects but am not clear on the layout of the blocks.
How many blocks should I have for running 2 trains? I have seen articles which show only one trigger section and one stop block. I suspect this would work most of the time but things might work smoother if I have multiple blocks.
How long should each stop block be? Should it be as long as the longest train? The objective is to stop the engine so I could see where the stop block could be only as long as the distance that the engine coasts when power is reduced.
How long should the trigger track be? I plan to have the trigger track overlap a stop block. Can the trigger track be only 2 or 3 sections of track or should it be the full length of the stop block? A full length trigger track would provide more certainty of stopping the following train in time but might be too restrictive.
Or perhaps I am spending too much time thinking this through and should just build a block and see how it runs?
I would appreciate hearing from those of you who have done this already and hearing what your configuration is and how well it works.
You should have the block long enough for the trains to pass and at least a nine or ten inches longer than the longest train so it don’t have problems at the switches from overhang of the parked train. The size of your layout is rather small so I don’t suggest having more than two blocks but you can see after laying the tracks and test running the trains. The trigger track should be as long as the engine plus one more section of track(ten inches).
I am not that up on relays for block sections, I wire mine with toggle switches.
I use 3 blocks with 3 inferred sensors. Going in a counter clockwise circle the sensors are at the counter clockwise end of the block. If train A is stopped in block one, in front of inferred sensor 1. it will not move until train B is no longer tripping sensor 2 at the end of block two. when train B approaches sensor 3 in block 3 it will stop if train A has not cleared sensor one in block 1… My insulated sections are about 30". Sensor 1 in block 1 controls insulated section 3 in front of inferred sensor 3. Sensor 2 in block 2 controls insulated section 1 in front of inferred section 1. Sensor 3 in block 3 controls insulated section 2 in front of inferred section 2… Hope this makes sense and helps you . If not just ask… sorry no space between paragraphs for some reason it wont let me. tried using ten spaces from the space bar and that did not work either. Now I will try the period.
Thanks everyone for your comments. I think that I will try three blocks on my loop.I will make my trigger track two 10" sections long with the stop block three 10" sections long and overlapping the trigger track. The blocks will be spaced equidistant around the loop so I should be able to run a 10 car train without getting into a mutual lock-up condition.
My plans are complicated by the fact that I already have a second loop intersecting this first loop with a 45 degree crossover and this crossover is controlled by relay logic to prevent collisions. So I have the somewhat unusual condition of a train on the first loop being stopped by a train on the second loop. This now determines the behaviour of the second train on the first loop. So its different than only a single loop which only has to control two trains on that loop. However it is do-able.