Yip, the BI&G RR would sort them according to the yard or railroad that they would be delivered to.
The yard master if there was one, or the conductor if there was not a yard master, would block the train the way they wanted.
They would not block by tow, but by the siding that they were to go to.
Here in Richardton, there are three sideings to be worked, but actually two of them are industries.
Red trail energy receves loaded grain (corn) cars, and empty tank cars, they ship empty hopper cars and loaded ethanol cars. Empties in or out could be handled by the local. Corn coming is would likey be on the local, since they do not come in so many at a time, but are frequently held here until BNSF wants to pull them out. BNSF has to pay the drayage on them no matter where they are left.
Ethanol going out would be a full unit train, so the car knocker from Dickinson would come down and inspect the train before the locomotive and the road crew arrives.
The Halliburton sand plant receivers covered hoppers of frack sand usually behind CP power since it originates on the old Soo line in Wiskonsin. BNSF will usuzlly pull the empties away before the next full train arrives. The CP power will have to go to Dickinson to fetch them.
Finally, there is the team track which could receive and dispatch cars on the local.
And so drayage is another factor that must be kept in mind.
SOMEBODY owns those railroad cars and they want to be paid for them no matter what. Drayage is the fee a railroad must pay to another railroad or other car owner for all the time that a car is on their tracks.
If BNSF dropos of a load of say salamander eggs at the team track, they will charge the consignee for each day the cars sits there being unloaded. They do not want to swallow extra charges just because you have not loaded or unloaded the consignment.
So even the shippers, the industries, or the local station master