how do i add a 3rd power pack (cab) using atlas selectors?

[Anonymous]

i am currently using 2 cabs on my layout. use atlas selectors for my blocks. want to add a third cab for my yards. how is this done??? thx

[dwRavenstar]

To have all three cabs available for the use in your yards you could keep the current selector wired to the yard, keep the first cab wired as is, wire the second and third cabs to a second switch and run the output from the second switch to the first on the prong now being used by your second cab.
Your current selection is between Cab A and Cab B. The new configuration will give selection between Cab A and either Cab B or Cab C, depending upon which you have selected with the second selector.
Gawd, I'm within three uses of the world record for having selector used in a sentence!!
[}:)]
Good luck with your project.
Dave (dwRavenstar)

[EMDSD40]

I currently use 4 MRC Control Master power supplies to supply my 4 track main PRR layout. I run 4 trains at once or any train anywhere. Iuse double layer rotary switches. Tracks are wired to center taps + and -. Then the power supply outputs are wired to matching sets of contacts. Turn rotary switch to select which power supply feeds which track.

[BR60103]

If you only want one loco running in the yards at a time, you could use a rotary switch with at least 3 positions. Then you could hook the 3rd power pack up to the center position, the other two to the outside, and run the yard from the new pack. When you want to leave the yard, turn the switch to one side and bring the train out on the main line throttle.
Otherwise, the Atlas components aren't designed for the job.

[davekelly]

I think you could run into difficulty if you want to run 3 cabs over the whole layout. I think it can be done with Atlast selectors.

You could use two sets of selectors. The first would direct power to either of two other selectors, one for cabs 1 and 2 and the second for cabs 3 and 4. Would be quite the pain I'm thinking as you would have to flip two switches for each block, but I think it is doable.

If you were to use a rotary switch I think it would be advisable to also have a on-off toggle for each block, that way you would kill the power. I'm thinking that with a rotary switch, even if you had an "off" position you would have to switch over positions controlled by another cab with possible bad results. While David's solution above would work, you could run into a problem if you have a train in the block thatyou want to control from say cab 2. If the switch is set for cab 1 you would have to pass over the position for cab 3. If cab 3 is being run by someone else, you don't know what the train on the block will do, thus the need for a on-off toggle for each block. Kill the power, turn the rotary to the deisred cab and then energize the block with the toggle. (this problem is not present with 2 cabs as the center position is off) Still a pain as you would have two switches to play with for each block.