Maybe the expression 'Freight' trains is a bit vague (although perfectly correct
). Perhaps it might help to pick a specific type.
Freightliner
Intermodal trains for example do seem to work to booked path (some of the time), and GBrF have some
aggregate workings which are regular movements also; eg - Mountfield to Southhampton.
On the other hand
Infrastructure trains seem less predictable, but this is not my area - Les is far better placed to say than me.
HTH,
Foggy