The railroad communications system rules covered the transmission of data between fixed points, moving points and between moving equipment and fixed points. Unlike most other applications, a railroad certainly has all three. It doesn't list anything as specific as frequencies I'm afraid, but it is a quick tutorial that was probably handed out to every yard man that might use a radio
"THE PURPOSE OF THIS BOOKLET WHICH CONTAINS BOTH FEDERAL COMMUNICATIONS COMMISSION REGULATIONS AND RAILROAD RADIO OPERATING RULES, IS TO SERVE AS A GUIDE TO THOSE EMPLOYES USING RADIO IN THE PERFORMANCE OF THEIR DUTIES."
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