Radio

Evolution of radios used within railroad locomotives

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 successor to the Motrac, the Motran, was essentially an upgraded version of the Motrac. Another early supply of early locomotive radios were Bendix, with their "2R54C Tranzistorized Unit" intended for locomotive use.

Railroads adopted a locomotive-specific variation of the Motrac, (see photo), and from 1958 on, this became the standard radio until around 1985. It was around that time that "CleanCab" radios were being introduced as part of the AAR's new CleanCab specifications introduced around 1972(?). The newest of these were the Trackstar (from Harmon), Aerotron, Harris, and Spectra from Moto.

Later additions to the lineup are Quest (Owned by GE), with thier not-so-popular-by-crews 12R-Series 2 and 3D, aswell as Ritron with thier legacy RCCR-151 and newer RCCR-NXR, incorperating NXDN protocol. Ritrons seem to be the most popular replacement for the Spectra, with crews noting they have "Nice loud audio and nice bright display screen". A newer modern radio is available from Railcom, offering their TrainmasterXD model. This unit is used heavily in Amtrak's Siemens Charger locomotives.

Locomotive Radio Trivia

Cleancab radios operate on 72vDC, with some (but not all) running on 12v aswell for bench testing. CleanCabs all use a standard powersupply connector from Amphenol.

Variations of the Motorola Spectra

There are a few variations from Spectra to Spectra, here's a few I have seen. These are definintly minor details, but are a few things to look out for. On the left side of the radio, there is a mounted rubber carrying handle, and some Spectras (mine included) have exposed screws, while others have the screws covered.

Another variation, is the rear rotational key for the locking mount on the bottom. Some railroads got thier Spectras with a mount that locks, adding a security aspect. Other spectras, like the one I have don't have a lock, but just a keyed, gripped handle. 

Railroad Specific Radios

Different railroads have made their own "in-house" radio, such as Santa Fe, with their "COLT", which combined HOTD data and a regular VHF radio. These were famous for being absolutely hated by crews, one saying that they had 1/4 the range of the other brands. The most repeated complaint is their lack of user friendliness. Noted examples of this is requiring three buttons to change a channel, and holding one while it slowly counts up. Some of these radios lasted until BNSF.

P42s - Spectra

Charger - Railcom

P32ACDM - GE/Quest

ACS-64 - Ritron

AEM-7 Spectra

GP40TC, GP15 - Aerotron

Metroliner, Surfliner, California Cab Car - Spectra

Acela, Old and New gen - Spectra

HHP8 - Originally came with Spectra, see this, 

Most SD70ACe - JEM 6.25

BNSF ES44C4 -  Ritron

BNSF ES44AC - GE/Quest