Evolution of radios used within the railroad industry

The very first radios with widespread use were the Motorola Motrac, and later the Motran. The Motrac was originally a vehicular radio intended for civil services, with GreenRadio labeling it as "Motorola's most successful entry into the Land Mobile Radio market" being the first radio in the US, and possibly the world to have a fully transistorized receiver. The sucsesser to the Motrac, the Motran, was essentially an upgraded version of the Motrac.