The thing is, is potentially 4 to 6 221s being available to XC because of this if it went ahead be enough to lengthen their core routes?
Obviously 222s will become available soon, but would there be enough to strengthen say most flows between the South West to North East and Manchester routes and potentially Reading?
It would allow the strengthening of quite a few diagrams, as for every new unit you got you could:
- swap out a 4 coach unit for a 5 coach unit
- steal a 4 coach unit from another diagram and run these as a pair in the place of a 5 coach unit
- use the released 5 coach unit to replace for the stolen 4 coach unit
Therefore even with 6 units 18 diagrams would see some level of capacity improvements.
However even that's not the full picture, as you could have the 8 coach train running over the core route. In the cast of the Manchester services (which appear to interwork with each other) rather than it being 11 hours for the complete cycle is the doubled up units ran Basingstoke to Exeter (which would take 9 hours) you save the need for 2 units, which could be enough to bring benefits to an extra diagram.
Given that there's 57 units, of we assume that there's 49 diagrams (5 units as spares/on maintenance and 3 units running in pairs already) 19 diagrams seeing improvements would be 39% of the services run by Voyagers.
As such for every Voyager service to see an improvement you'd need 16 extra units, you may get away with a few less than that because some services don't need to see an improvement (as they are already doubled up) or they have a significant of their route off the Core network (i.e. they run West of Plymouth and therefore off the Core network for a longer period of time).
As such with 12 units you'd probably see most (getting close to nearly all) services run as 5 or 8 coach units over the core. (i.e. 32 X 5 coach units Vs the current 38 X 4 coach units, with some of those being run in pairs currently and 19 X 8 coach trains Vs 20 X 5 coach units).
12 extra units is what you'd get of the Liverpool services were every other hour.