If NorthsideTo add to what Chet said and to make Larry Jackman grit his teeth.
If Andrews Pre-stress were to order a bulk load from NW States in the
50s. The plant would load an M&StL hopper. The M&StL would pick up the
car and take it passed Andrews (1 mile SE from plant) to weigh the car
(3-4 miles SE from plant) then take it back north and spot it at
If a lumber yard in town on the Milwaukee wanted a car of bags. Then
the Milwaukee would give one of the RRs servicing the plants an mty box
car for the plant pool on a transfer track. That RR would take the car
to a plant and pick up the box car billed to that lumber yard. They
would spot the car on the transfer and the Milwaukee switch crew would
pull the transfer and eventually spot the car at the lumber yard.
We modelers call this 'operations'.