Dual controller question

[Bigboy57]

Ok, this may be a stupid question but I'm going to ask anyway. My layout is a DC single track bent dog bone with two reverse loops which allow a train to run around the layout in either direction. If my reverse loops (the red ones) are isolated from the main loop electrically can't I run those loops off a second controller and while the locomotive is on the loop simply reverse direction of the main line controller?

 

[dennis461]

Yes

 

[Bigboy57]

Thank you Dennis. This seems like the simplest solution rather trying to incorporate a dpdt switch and still having to reverse the main line.

 

[Iron Horseman]

This seems like the simplest solution rather trying to incorporate a dpdt switch and still having to reverse the main line.

Might be "simpler" to wire, but your operations is going to be tricky matching speeds on the controllers and hoping the wheels crossing the gaps don't cause a double short circuit, or the locomotive doesn't get double voltage when the power of the two controllers is reversed from one another.

 

[Bigboy57]

Might be "simpler" to wire, but your operations is going to be tricky matching speeds on the controllers and hoping the wheels crossing the gaps don't cause a double short circuit, or the locomotive doesn't get double voltage when the power of the two controllers is reversed from one another.

Hmm. Please explain more. If I forget to reverse the main loop controller while on the reverse loop I could see a problem but the double short circuit scenario I don't understand. Thanks

 

[Iron Horseman]

If metal wheels would cross and span the gap on both rails simultaneously the power from each pack would be connected. With power reversed, the units would be in series with each other with no load. They would basically be both short circuited at the same time.

 

[Bigboy57]

If metal wheels would cross and span the gap on both rails simultaneously the power from each pack would be connected. With power reversed, the units would be in series with each other with no load. They would basically be both short circuited at the same time.

Ok. Aren't we saying the same thing here? If the main line is not reversed while the loco is on the reverse loop a short would occur when the main line is reached by the loco???

 

[Iron Horseman]

Ok. Aren't we saying the same thing here? If the main line is not reversed while the loco is on the reverse loop a short would occur when the main line is reached by the loco???

Yes, but I thought your question was why was it a "double" short circuit.

 

[Bigboy57]

Well, I tried it with the dual control method and it worked nicely with newer dc locos which had all wheel pickup but older locos stalled at the insulators. They didn't like getting power from two transformers when they only had pickups from one wheel front and one rear.
I wired a dpdt switch and that takes care of things for now. When I switch to dcc I will use auto reverses for the two reverse loops.
Thanks for your interest.