Actually it could be a bit of a problem, as unless they lengthen all the platforms at Queen Street, then they will be forever 4-car where 3-car units could be doubled to give 6-car.
Some interesting info in the final business case
http://www.transportscotland.gov.uk...BC_ Publically available version_27012014.pdf
Looks like the upgraded design for Queen St station might involve additional track works compared to the Jacobs proposed design of 2012. That only involved lengthening platforms 5, 6 and 7 to take 8 car trains.
The new business case now prices this upgrade at £120m, up from £50m so obviously more work is happening and it looks like demolishing the SPT offices is definitely on the cards now, I wouldn't be surprised if the new plans don't include additional 8 car platforms for flexibility of service: especially platforms 1 and 2. Either way we should know soon as:
Transport Scotland Jan 2014 said:
The project scope has developed significantly since the July 2012 announcement of the first phase of EGIP and now includes the redevelopment of Glasgow Queen Street Station, outline plans for which will be revealed by Network Rail next month
Of course 8 car operation on the Stirling route would still need either SDO or platform extensions. The final business case confirms platform extensions are the preferred solution at Croy, Falkirk, Polmont and Linlithgow so the stock may not necessarily be SDO compatible?
If not then running a 96m train on the Stirling route would need extensions at most stations. I think Stirling (exc Bays) and Dunblane can take longer trains but Alloa, Bridge of Allan, Larbert, Camelon, Falkirk Grahamston, Lenzie and Bishopbriggs would all need extending. Possibly this is part of longer term plans but they aren't wanting these costs to get included in EGIP (and hence lead to negative "costs rise" headlines?
The other interesting thing in the Final Business Case is the return to explicitly talking about Phase 2 in 2025 with Greenhill, Croy, Dalmeny chord etc all back on the table as a second phase rather than ditched altogether. Suspect that this will depend how the perform as an option against the new high speed line though.