There were a couple of possibilities. The Motorola Railroad radios of that era were the Motrac and the Motran. The Motrac had some tubes in it, the Motran was all solid state.
There were two mounting options. There was a "one piece" that had the control head mounted to the top of the radio and a telephone handset fit in a cradle on the top of the whole assy. Usually this was a two channel control head if I remember.
The other mounting option was the standard AAR radio mount chassis with remote head (2 or 4 channel as usually seen in Locomotives).
Both radios could be set to run on 72 (64) volts or 12 volts DC.
Can't remember the model numbers (think they began with R43, maybe if you Google it). These radios were a variation of the standard Motorola land mobile product, factory made with special power supplies and interface for Railroad use.
Fixed hundreds of them for Conrail in the 70's.