Railroad crews all have crew seniority districts. Crews are based from a terminal within that district. The runs are usually round 100-250 miles. They may go in several directions from that terminal. Railroaders are not like truckers, and do not stay out for long extended periods. Usually you would make a run to your away terminal, then come back following your mandatory rest period. The reason is because crews have to be familiar with every speed change , signal, switch, and road crossing. This is because a train can't stop within its line of sight like a car or truck. Someone can't possibly keep up with remembering the whole NS system. Not all crews are on the road. Local crews may switch out industries along a line but return back to the home terminal every day. Yard crews also switch cars in one and all day long.
There are times when you may get kept out for a week or so. Sometimes there is an excess of guys in a terminal, but a shortage in another. They might force the junior guys to the other terminal, until the terminal with the shortage of manpower catches up. There are sometimes work trains which tie up nightly along the line. Some might run a week or so in duration. Usually these trains lay out materials for track repairs such as ties, rail, or stone.
Other employees beside train and engine crews are required to travel. Certain engineering crews may work somewhere for a month or so repairing track and bridges.