I am interested in running 2 trains on one loop and would like to know how to do this. I would like to setup blocks and use relays but am unsure what relays to use. I found this:
I’m not sure if that is expensive or if it will work and how it will work, but I have a gift certificate for that website so I would like to buy from them. I already have signal lamps for decorative purposes and I would like them to change from red to green, etc. while the trains stop and wait for the blocks to clear. I just don’t know what type of relay I need, and how to wire them. I have O-27 and O engines and a new ZW transformer.
Isolate one outside rail around the entire loop. Put a break in the isolated rail at each block boundary. These isolated rail segments are called “control rails”. Isolate a center rail for a short distance ahead of each block boundary, on the side facing the signal. Make this “stop rail” long enough for the locomotive to stop when the stop rail is unpowered, probably a couple of feet.
Connect the center rail also to the common of the relay contacts. Connect the normally-closed relay contact to the stop rail and to the green lamp of the signal guarding the block. Connect the normally-open relay contact to the red lamp. Connect the signal common to the layout common, that is, the outside rail that is connected to the transformer’s common terminal.
You might also consider a Lionel 153C contactor. The 153C utilizes train weight to switch power off/on to another block, thereby preventing rear-end collisions on the loop. (Note: The insulated blocks have to be set up before installing the 153C.) It’s a simple, but effective way to space out two trains. (I use one with an old AF semaphore.)
Try searching eBay under “Lionel 153C contactor”. Currently (as of this posting), there a several available (some with original instructions) for less than $15.
Thank you so much for the post. Isolating the outside rail sounds like quite a challenge since I am using 0-27 track, and plenty of it. Would paper be sufficient to isolate the rail from the metal track ties? Is there a better way?
Relay + Bridge Rectifier can be found at Radio Shack. Also pick up some barrier strips to help making connections.
The 153C contactor does not work very well. If using a Lionel 153 Block signal it is easy to power the lamps from the ZW Transformer. If using LED lamps for signals, then you will also need to get the correct resistors and diodes and / or another Bridge Rectifier to power the LED lamps.
I looked at your link to Tower Hobbies for the Atlas Snap Relay. I tried using it with the outside control rail track section and was able to make the relay control the block signal, Green to red as the train went over the first control rail, then back to green when it got to the second control rail. But the problem with the snap relay is that is only to be used for a very short time, like a 1/2 second. I found that when a train is rolling over the control rail the relay is energized for too long a time, the relay gets too hot and the plastic body gets too hot and begins to melt the plastic.
The 153C should be properly installed where the track has freedom to move up or down according to train weights. (You may need to double-check the track sections on either side of the 153C for up/down flexibility.) There is a spring-loaded thumb screw adjustment for fine-tuning the switch mechanism.
Also, check the weight of the trains running on the loop. The 153C will not be as effective if one train is significantly lighter than the other. I put some iron ore pellets into a hopper to add weight to one of my trains. Sand or gravel could be substituted.
My 153C contactor works perfectly after a few adjustments. It just requires a little trial and error.
