DC One power pack to another...

[Dougget]

Hi,
I just read an article in MRR magazine about cab control. I'm thinking about something similar for my layout, but wanted some feedback before I try it.

Basically, I will have an inner loop and an outer loop with a crossover to connect them. The plan was to insulate the crossover turnouts from each other with insulated rail joiners.

Setting 1: The turnouts are set to straight and I would control the inner loop and outer loop independently with two separate power packs.

Setting 2: The turnouts would be set to crossover and I would need to make sure the two power packs were set at the same power level while a locomotive was crossing over (from one power pack to the other.

My concern is, in the crossover mode, there will be a time when the loco is spanning the insulated rail joiners and getting power from both power packs. Is that a problem?

Is there a better way (without DCC)?

Thanks,
Doug

 

[kjd]

Cab control is controlling which cab is supplying power to which track. Usually this is accomplished with double pole, double throw electrical switches. A DPDT switch has 6 terminals and it switches power from one of two sets of supply terminals to the two terminals connected to the track. Cab A is connected to one set of terminals, Cab B to the other and the track the remaining two.
I would divide your two loops into at least 4 electrical sections (blocks) for 8 total. One block in each loop would contain the part of the crossover for that loop. Two trains could be run, one on each loop. When crossing over one train has to stop and then the other half of the crossover switched to the other cab and the train run to the other loop. The reason for 8 blocks is that there can always be one block between the trains.
Come to think of it, DCC is much easier.
As far as the locomotive getting power from two cabs, I don't think it hurts anything as long as they are closely matched in speed. I don't know what would happen if one happens to be the wrong polarity, hopefully they have circuit protection that would shut everything down before something lets its smoke out.
Back when I had two cabs I was running Athearn engines with no circuit board in them and one piece of wire connecting the motor to the trucks. There wasn't much to hurt, they were pretty indestructable. I don't know how newer, much more electrically advanced locomotives would handle anything going wrong.