This was a SWITCH LOCK on the ICRR (Illinois Central Railroad). It is a solid, heavy steel lock, and shows some heavy usage. There is no key.
The manufacturer's name "ADLAKE" is on the key cover plate in raised letters. The railroad name "ICRR" is stamped into the back side of the lock body. There is a number "3" in a frame stamped into the shackle on the back side. There is no chain attached. There are several dents along the edges of the key cover plate that look like it was hit with a hammer,also slightly bending the plate, but it still swings to cover the keyhole. There is a small bar-shaped dent in the front near the top left that looks like it was intentionally struck into the lock. The lock overall shows use0 with the normal expected tiny dents and scratches in the body. The steel of the case is really quite rust-free for its age. The shackle is a bit rougher from the original casting process. A nice lock.
The main body measures about 3.5" tall.