The 1950 issue of Railway Signaling and Communications (Volume 43) contains numerous ads for communication products. It is a good illustration of the state of the art of that time. Electronics and improved materials were entering the marketplace.
The Automatic Electric Company, of Chicago, was a competitor to Western Electric and marketed equipment specifically for railway applications. Railway telephones had to work over long distances and be rugged. Some of the ads are described below.
relays and switches had to be rugged for railway service.
telephone sets had to be dependable
hermetically sealed relays
Carrier channels to increase single line capacity.
In addition, railroads were using IBM tabulating machines and early data communications via telegraph to interconnect them. That is described here.
You may scroll through the rest of the issue. Two notable advertisers with numerous ads are wire/cable makers Okonite and Kerite, both touting the toughness and durability of their cable insulation. Other industrial suppliers advertise batteries and electrical tape.