I thought about how to run a semi hybrid network. You have a network programmed in which people rent slots on to use track Say 1 slot pr mile of single track.
London to Edinburgh- 400 something miles. 400 slots of trains. Say its double track you double that becauses there is 400 mile of two tracks so 800 slots.
Also you can if the track has no slots left you can Build An extension of existing track. So add to currant track. Say 100,000 per 100 miles of new track.
You may also want to add slots for a station. You could also do the same and extend station and add more slots if slots are in short supply.
Thanks
Hope this is of Value
Fly Europa