Multiple train block control without relays - diagram of

[Birds]

In the thread "Recommend train gage for starter" (http://www.trains.com/community/forum/topic.asp?TOPIC_ID=56153) I mentioned automatic multi train control without using relays or 153C type contact switches. "lionelsoni" provided a nice description of his setup.

I'm going to elaborate a little more incase some newer folks to the hobby are still coming up to speed on wiring.

This configuration can also be applied to trains arriving and waiting at switches/turn out for other trains to pass.

Here is an ASCII art diagram of four sections of track to help explain (I didn't have a place to upload a JPEG).

|A--------------A|-------------------------|B--------------B|--------------------|
|------------------|--------------------------|------------------|--------------------|
|------------------|--------------------------|B--------------B|-------------------|

A = one section of insulated track where one outside rail is fully insulated from the metal ties and has fiber insulating pins on each ends. You can make these insulated rails yourself, or you can purchase them.

B = is one regular section of track with the two outside rails isolated from the rest of the layout by removing the steel pins on the outside rails, and replacing them with fiber pins. The two outside rails in B are not insulated from the metal ties. Current is allowed to pass over the ties.

The insulated rail of section A is connected to one of the isolated outside rails of section B by a lockon, or by inserting a wire into the slot on the underside of the rails.

When a train moves onto section A, the wheels and axles act as a simple knife switch, and current flows between the insulated outside rail and the non-insulated outside rail.

Because isolated track section B is connected to the insulated rail A, current is now allowed to flow from B to the isolated rail on A, across the wheels and axle of the train to the non-insulated rail on A, and then back to the transformer. This completes the circuit and the locomotive stopped on B can now move.

Center rail power is continuous through these four sections and is not blocked by fiber pins at any point.

Hope this helps,
Birds

[jimhaleyscomet]

Great explanation! Thank you.

Jim H

[ADCX Rob]

The one drawback to this method is when used w/ Prewar & Postwar(Modern too, for that matter) locos & rolling stock with metal wheels, axles, & trucks.

These parts do conduct common rail current forward to the locomotive and will "coast" a train through the fully insulated block with amazing regularity, and with an often jerky motion as the current works its way through the couplers. Also, each time a wheelset crosses a live section into the insulated section, the consist will get a little "boost" - even if all the couplers are plastic and only the wheels are metal. It can be an interesting light show!

Rob

[lionelsoni]

I simply make the B section long enough for the entire train, and the A section long enough to get the stopped train out over the gap to normal track.