49 CFR 1312.7 - STB tariff designation.
(1) The characters “STB”;
(i) The tariff number (selected by the carrier or agent) to distinguish that tariff from all other tariffs filed by the same issuing carrier or agent. Tariff numbers shall not exceed 5 numerical digits and may be followed by not more than 2 letter suffixes. Examples of tariff numbers are:
(c) Fees for assignment. Fees may be assessed for the assignment of codes, but may not exceed the processing costs.
(d) Code listing. A list of the assigned alphabetical codes, and the names of the carriers and agents to which they are assigned, as well as subsequent changes to the list, shall be submitted to the Board's Section of Tariffs.