I see, sorry. I thought you meant the 2nd tph should be entirely new.
Indeed, I wouldn't stop the expresses there. But if no services are being added, then it's not worth cutting service, and indeed no other station should lose theirs. I do just think that running half the train express would be a sensible yet relatively affordable improvement, and would go some way to bringing the line back up to true "Intercity" status.
It's a bit of s stretch to suggest that the line ever had true InterCity status - even before the worn-out track forced the removal of all but a couple of Hereford-London and back peak trains, the service in the 1960 and 1970s was in reality not much more than a semi-fast operation with an assortment of Western Region traction - Class 35, 42, 47s (best not to mention the 31s...) and Mk1 or early Mk2 stock, backed up by a few dmu stopping services in the peaks.
Its development since all-day running to and from London was reinstated in 1993 has relied heavily on income generated at the eastern end of the line - which then helped to fund extension of services all the way to Worcester, rather than turning them round at Moreton-in-Marsh, especially in the evenings - and then bolstered since 2006 by increased numbers of trains calling at Hanborough (and the expansion of places nearby, notably Witney).
For all the success of Worcestershire Parkway, a lot of traffic there is on the north-south axis, not the Cotswold Line, and if it and the city centre stations are worth a 2tph London service, then you can make a case for the same at most of the busier stations between Worcester and Oxford.
Interesting to read expert opinions from outside the Oxford-Hereford route catchment area.
The speeding up of the journey times from Worcester to PAD from the HSTs time of 2hrs28 min to 2 hours/2hrs.5 by IETs has helped increase passenger use.
The North Cotswold Line Task Force proposals, supported by all the County and District Councils along the line, meet the identified passenger demand for stops between Evesham and Worcester especially for onward journeys to Kidderminster and on the eastern side of the Camden Tunnel between Moreton-in-Marsh, Kingham, Charlbury, Hanborough and Oxford.
Ten car 800s are a rarity but the those 9 car units in the timetable to meet recognised demand are near to capacity after Moreton in Marsh especially on Wednesdays and Saturdays. So when the 5 cars unit are used at short notice to replace 9 car units it leads to crushed services in the mornings.
If PTR44 suggestion of of train splitting is implemented, I will invite PTR44 to be present at Oxford to meet travellers there, as it was customary when Thames Turbos were used but was very unpopular, not only by passengers onwards to Worcester but those at Oxford. The introduction of HSTs was widely welcomed as they provided a faster continuous journey.
Perhaps "Local solutions for Local needs" is the best way to go forward.
HSTs were in use on the line long before the first Turbo left the production line.
Splitting and joining of services at Oxford was reduced for several reasons - XC starting to run 2 tph between Banbury and Oxford and the switch of the London to Stratford-upon-Avon service to Chiltern Railways operation, thus reducing the number of GW services needed between Oxford and Banbury - and the introduction of Class 180s on London-Oxford/Cotswold Line services by FGW from late 2004. It also had the added benefit of freeing up platform time in Oxford station that the coupling and uncoupling had required. Portion working was more of a headache at times of the week when lots of non-regular/leisure travellers were around - regulars knew to be in the leading set of a formation leaving Paddington or Reading and to wait at the north end of the platform at Oxford - and Oxford passengers weren't at all fussed by it in my experience, as they could use any part of the train.
I have used the North Cotswold Line on one occasion (Oxford - Charlbury last year) and I can tell you that the train I was on, a 5-car IET, carried fresh air pretty much all the way. Heading London-bound on the other hand, you’d be amazed just how many passengers get on at Oxford to fill the train up from an empty 5-car to a full and standing 10-car service.
PS: I didn’t realise some services on the North Cotswold Line used 9-car trains. Maybe I just traveled on a very quiet day.
And on which day and at what time did you make this journey?
Like just about any route across the country, loadings vary across the day and week. So yes, there are some Cotswold Line trains where a 5-car set is quiet, while there are others that are busy enough to need a 9-car set.