Co-operation? In the rail industry? Unless they are forced to by the government, not a chance.
You obviously don't work in the industry.
What about Scotrail/Northern on the Newcastle-Carlisle-Glasgow services?
Co-operation? In the rail industry? Unless they are forced to by the government, not a chance.
Central and Silverlink County services shared the 350 fleet and units changed crew at Northampton - passengers could treat it as a through train.
Southern train crew operate some FGW Gatwick services...
FGW train crew used to operate SWT's Penzance trains in Devon and Cornwall...
It's rather the reverse; the Government / ORR insists that franchises are operated separately. This is so that, in extreme circumstances, they can stop a franchise and let it to an alternative operator. If, for example, all of the First franchises were pooling management and engineering resources that would not be possible.
There is some cooperation, generally to cope with unplanned events, as described in other posts.