common rail wiring

Model Railroader Layouts and layout building
1

I have a DC common rail problem. I have a 5 block set up and I only can get one to work. I have one cab feeding one side of all spdt toggles and the other feeding the opposite side. The center lead goes to the blocks. The common rail is wired to the cab. This is a large oval, no reverse loops. Any suggestions?
Frank

2

I’m going to assume you have checked that all 5 toggles are the same in their terminal designations so they are indeed connected (electrically) as stated above. Also that you have feeds for the common rail going to all blocks, especially past turnouts.

The first thing I’d try for troubleshooting this is to disconnect one of the cabs completely from the setup and see if all 5 blocks can be controlled from that cab. If this works, disconnect the other cab and reconnect the first one and try it again.

If it doesn’t work with one cab, you can troubleshoot a simple block system problem. Insure all wires are connected properly to all the tracks from the toggles. Start by comparing the block that does work with the blocks that don’t.

If it does work with one cab at a time connected, you may be getting a feed through from one cab to the other which will short it out.

Also, are your cabs two separate power packs or one dual pack? A dual pack can cause REAL headaches when you use common rail wiring.

3

I can’t tell if you have the right idea by your post, but I can’t see where your mistake is either. A few questions to check out the basics …

  1. You have 5 blocks on your oval layout

  2. Do you use the inside rail or the outside rail as your common rail?

  3. Do you have the other rail divided into five sections (block rails) using insulated rail joiners? If both rails are divided by insulated rail joiners, do you have a common bus wire connection to this rail in all 5 sections?

  4. Are both cabs properly wired to the common (ground) rail?

  5. Have you verified the switches operate as you think they should by checking continuity on the poles?

  6. Have you checked for shorts in your feeder wires to the block rails?

My suspiscion is that you have inadvertantly reversed the common bus wire to the wrong side somewhere along the way, but that is strictly a guess. Good Luck.

4

I don’t know if this is just an English error or not, but as Dinosaur stated in point #4, the common rail should be wired to both cabs.