Here is a brass switch key from the CSX Corporation, which was formed in 1980 by combining the railroads of the former Chessie System with Seaboard Coast Line Industries. This key appears to be an earlier one, and has only the railroad CSX reporting mark with no maker mark.

This key shows light use with the barrel end and bit not quite sharp. It has darkened to an attractive color. See our pictures: there are some inconsequential filing marks on the inside of the bit.

This is the time to pick up keys from roads of the 1970s-1980s.