What is ROB - define ?

Define ROB (Railway Operating Battalion)

(Source: Military Railway Service, The General Board Study No. 123)
The basic operating unit in the ETO was the Railway Operating Battalion consisting of four companies:
HHC in charge of administration, train dispatching, supply, communications, and signals;
Co A responsible for maintenance of way and strcutures;
Co B operated the engine house and made running repairs of motive power and rolling stock;
Co C was the actual operating unit, with 50 train and engine crews.
This basic operating unit was capable of operating 90 to 150 miles of track with not more than one terminal with classification yard facilities. The Bn consisted of 29 officers and 790 EMs.
The Railway Shop Battalion was responsible for maintaining and repairing rolling stock, and was equipped to serve from three to four ROBs.