marshalling yard 
noun British
A large railway yard in which freight wagons are organized into trains.Chalk was important to yard operations for without it switching freight cars in marshalling yards would have been slower and much more difficult....
- For many years, chalk played an important role in everyday railway operations in freight marshalling yards.
- Stations were often the scene of innovations because they had problems in parcel handling, rolling stock shunting and above all wagons in marshalling yards.