Which nine-car high-speed diesel units would these be? The overwhelming majority of the London-Cheltenham services in the new timetable are going to be operated by five-car IETs.
And plenty of the people in Cheltenham, Gloucester, Stroud, Stonehouse and Kemble/Cirencester would quite like to have a frequent through service to and from London - which is what they are supposed to get now - rather than being tipped out at Swindon half of the time.
The issues over staff availability today - and much of the rest of the time - appear to be concentrated on a limited number of traincrew depots.
In the Thames Valley they seem to have more volunteers than needed today, as there are hourly extras running each way between Paddington, Reading and Didcot, on top of the Cotswold Line services and the new extra London-Oxford fasts (which all call at Didcot on Sundays), and the remaining Paddington semi-fast services sharing the reliefs with TfL east of Reading.