How did they do that?

[lionelsoni]

It can be done without relays or anything else if you are willing to have one vehicle depart before the other quite gets there. Just isolate both outside rails of each loop inside the shed. Then connect all the isolated outside rails of both loops to control rails leading to the shed in both loops. As one vehicle approaches the shed, it crosses the control rail, grounding the outside rails in the shed for the other vehicle, which then departs. When the first vehicle reaches the shed, it stops, since its outside rails are open. This will even work with both vehicles on the same track, as long as they run at about the same speed.

[FJ and G]

I think it's done with relays and a control rail but others more knowledgeable will know.

I've performed this trick with DCS recording, set on "loop."

[jonadel]

I was watching a video the other night (MTH Great layouts #2) and one of the layouts had loop for the trolley and a handcar. When the trolley would return to the shed it would stop and then the handcar (on a siding) would go out and return and then trolley would go out. Is that an easy wiring trick? I'd like to give it a try and I've got just the spot for such a set up.

Thanks

Jon