Listed below are standard frequencies used by railroads in the United States. Similar/same frequencies may be used for crossboarder operations with Mexico and Canada. The American Association of Railroads (AAR) has assigned channel numbers to each standard voice radio frequency.
Such channel numbers are used with railroad radios and are commonly referred to by field personnel. Locomotive radios are able to select individual transmit and receive freqenices as needed. Sometimes this can be heard as "Go to 20-90". Standard practice is simplex operations, with the same channel number. A common channel for Union Pacific is channel 020, and may be herad on the radio to goto Channel 20. Railroads on the radio still use the old channel number as opposed to the new numbers, where appropriate (ie "20" vs saying "020").
The AAR standard for digital voice radio uses the Kenwood/ICOM NXDN/Nexedge digital format in 7.5KHz channel spacing. There is no mandate to use digital, but those locomotives or operations that are required to interchange with other railroads must use NXDN, if digital radio is used.
Regional or smaller/tourist railroads have been known to use channels or trunked radio systems outside of the AAR plan. If interchanging with another railroad, the AAR standard will typically be used.
Amtrak/passenger trains oustside of its own rail lines can be found on the host railroad's radio channel. Station operations may or may not be on a separate channel. Trains from another railroad company operating on another railroad will be found on the host railroads channels (IE a Norfolk Southern train detouring on CSX)
Railroad radio operations are additionally found in each states railroad section.
Frequencies
Railroad Operations
AAR 001-097
These channels are part of the original AAR band plan, and are widely used in the United States. After the narrowband mandate, AAR relabeled the channels with a 0 (zero) to indicate that the channel is now narrowband. Channel 24 (25 wide) became 024 (12.5 wide) and the frequency remained the same. Channels 001-006 are used in Canada and in the US by some railroad trucking operations.
AAR 107-196
AAR 307-487
Advanced Train Control System
Positive Train Control
Positive Train Control or PTC is a new GPS and data system to enforce various railroad and federal rules pertaining to train movement. Most railroads will be required to use a form of PTC currently offered by two vendors. This system is designed to be interoperable with other railroads to allow standardizing of data and equipment. Some isolated or passenger railroads may use their own form of PTC such as Amtrak's ACSES on the Northeast Corridor. PTC is independent of other forms of signaling such as ATC/CCS/ATC, but may be overlaid with signal systems. Although there is no dedicated service for PTC by the FCC, railroads have selected the 220MHz spectrum for PTC operations. These frequencies are licensed nationwide.