I just returned to model railroading after several years. My layout dates from 1990 when I was living in Germany and I'm gradually re-wiring it to add DCC and to add things like LED lights. Way back I bought some, what I think are, block detectors. I'm modelling HO and my set was for Fleischmann DC trains.

The black plastic case is 45 mm long X 37 mm wide and 6 mm thick and has two mounting tabs, one on each side of the case. There are five brown plastic tabs along the bottom to solder wires to. Each brown tab has three solder points. Unfortunately, the case doesn't have a manufacturer name or part number. The wires would seem to connect to power, track sensors and track signals. Embedded into the top of the case are symbols which look like a wiring diagram for relays.

I'm hoping someone could help me identify it and lead me to a schematic. I think it's DCC compatible as it relies on sensors embedded in the track bed and not to any track wiring. The sensors (not shown) are about 7 or 8 mm long and look like long grains of rice about 3 mm in diameter.

That is the Roco10019 bistable relay with 4 outputs and one input for controlling on/off to accessories & track power. I have plenty of those in a drawer.

Good universal electromagnetic relay, very usable on a layout and very reliable.