This circuit is from a time when this type of feature was not common in line cars. The pulse transformer has a 1: 1 turn ratio and the SCR admits equivalents.
This basic configuration can be found in a lot of articles on this site. In this case, the relay...
This high pass filter was found in the February 1996 Electronics Now magazine. The circuit...
Found in General Electric documentation from 1967, this circuit uses an unusual PUT today. The...