Channel 38
Hi Viper,
The frequency 160.680 mHz is ARR channel 38 - the railroad frequencies have "channel" numbers assigned to them much like marine frequencies do. The fact that "3838" showed up as an accompanying ID means either that you are using pre-loaded service search or you uploaded the channels numbers with the frequencies when you went to railroad search.
The fact that the channel number (38) is repeated reflects another railroading convention. Most railroad radio communications are simplex: the locomotive and the land-based station transmit on the same frequency. In the case of 160.680 mHz, the channel use would be noted as "3838."
Some railroads use duplex communications: the train (locomotiove) transmits on one frequency and the dispatcher transmits on another. In that case, the channel designation would be 3865 (just an example) meaning that the locomotive transmits on channel 38 and the dispatch transmits on channel 65.
Hope that helps.