Here is something that is kind of hard to find but that you really need to hook up that prewar 078 Block Signal. This is the 078-7 contactor. It can also be used for other accessories but is most commonly used with the standard gauge block signal.
This one is used but clean. There is no visible printing on it. (See our other listings for one with strong Lionel printing!).
If you are up to it, the arms can be adjusted to fit O gauge as well (there are other slots for the clip to fit it in to move it back). It is currently set up for standard gauge.
CONDITION: Used. C-6+ Ready to use. Does have some light wear, and has most of the original print rubbed, but the metal contacts are still cleaner than most we have seen. Has been used.