From what people have been saying on the Pacer replacement thread, sounds like extensions are going to be handed out in bucketloads, highly doubt any train operators will replace fleets quickly enough!
I'd be interested to see what happens with the East Midlands Trains fleet with the change of franchise. Personally I'd like to see some of those spare TPE 185's (Or some other out of lease DMUs) go to the Norwich-Liverpool route and maybe have more 158's cover the local routes but that's definitely being overly hopeful!
When the franchise changes existing rolling stock will remain in place until replacements arrive, be they new or cascaded.
Back in post 691 I said;
"HSTs will be kept in service as they would cost too much to bring up to modern standards before bi-modes arrive. There isn't time to do all the upgrade work needed, and the fleet's too small to release the units for such major work. There isn't capacity in workshops to do it anyway. Work on GWR and Scotrail units prove it's not such an easy job as some may have imagined. Sliding doors and retention toilets both require a lot of work. A dispensation for the life of the units seems likely to be agreed."
At the East Midlands Stakeholder Conference in November the word dispensation was used to cover the operation of non-compliant vehicles. That was explained as different from derogation! I hope I got this right.
Derogation may be taken to mean where the stock is being made compliant but it may not be ready in time to comply by 31st December. The vehicles will be made ready and have a future.
Dispensation is where there is currently no refurbishment even planned. These vehicles are condemned and will be replaced as soon as new or cascaded stock becomes available. As there is not enough suitable stock likely to be available for a couple of years or more it seems quite a few units will continue to run much as originally built.
The 185s are another matter. The Sheffield-Manchester part of the route needs at least 4 coach units if not 6, so 3 x 158s would be fine. Loading can be equalised by walking through the train. Now that stock is normally available to send out 4 car trains the East Midlands third of the route is the best to catch - to get a seat. (It's not if punctuality is wanted.)
At present TPE 3 car trains are totally inadequate on many services. However, 6 coaches can be excessive on many journeys, particularly east of Doncaster. When 6 are most needed one half can be full and the second has space.
40 years ago the standard trains between Sheffield and Manchester were 4 car Class 124s, but that's another story. Traffic on the route has probably trebled since then.