Channel	MCP (MHz)	BCP (MHz)	Predominant User
1	896.8875	935.8875	Union Pacific
2	896.9375	935.9375	CSX
3	896.9875	935.9875	Shared ATCS Network
4	897.8875	936.8875	BNSF
5	897.9375	936.9375	Norfolk Southern
6	897.9875	936.9875	Southern Pacific

ATCS frequencies are typically registered to the Association of American Railroads or Transportation Technology Center, not the individual railroads themselves, so use those names in Percon or FCC database searches to determine if there are any transmitters in your area. Alternatively, simply search for any one of the MCP or BCP frequencies, since apparently all MCP's are registered for all MCP frequencies, and all BCP's are registered for all BCP frequencies.

To receive both sides of the "conversation", program your radio to rapidly alternate between the frequencies of a channel. On some radios, maximum speed may be obtained by programming an entire bank with alternating values. Also be sure to disable the "delay" feature.