Not cleared south of Westbury to my knowledge and I think I've understood there would be issues as there are with some other trains at Hamble Bridge - but it's surprising what can be done with a bit of encouragement

 

There is a certain amount of history to where we are today.  If go back about 10 years the plan was electrification to Swansea, Bristol and Oxford.  This was abruptly cut when costs were overrunning.

The IETs were originally in two types (known as class 800, and 802).  800s were planned with lower power engines and smaller fuel tanks for slower add on services to South West Wales, Cotswolds etc.   When the electrification got cut back they were modified to be like the South West sets (class 802) to go further and faster on diesel.

The original plan also included running double sets at London end (where track capacity is limited due to number of services) splitting with single units going on the west, splits would have been at various eg Cardiff, Swansea, Exeter, Plymouth etc (depending on demand and time of day).   

But there was a problem, when old fashioned analogue train protection was turned on, software threw a wobbly and needed to run through a whole boot up process to talk to the protection.  The result was after coupling or uncoupling train had to wait many minutes whilst software reset.  This scuppered the idea of joining and splitting services en route.   The timetable was changed and the large number of short units ended up working as double units throughout, even to the remote lower passenger numbers parts of network

GWR ended up with 36 5car and 21 9car class 800, and 22 5car and 14 9car class 802.  Totalling 56 5car and only 30 9car units.

 
I am learning a lot of train sets, and journey lengths in this thread.

So why would GWR-DfT agree a franchise deal with inadequate stock for the range of train journeys that they have to do, and why do they have an excess of 5 car IETs?

 
Are 5 car IETs capable of Cardiff - Portsmouth ??  Quad mode: OHLE, 3rd Rail, diesel, battery 

 
Even after the 175s arrive, still not going to be a very good match for GWR services

The 10 2car 175s could take over a few Paignton, Exmouth services from 150s, but their longer distance seating and door layout is not ideal.   For most other services operating them as just 2car is likely to give capacity problems at certain times

The 16 3car units will be more useful, although there are number of services to Barnstaple, Oakhampton, Newquay etc where passenger numbers ideally means they will need to be longer formations.  However some of these services have stations where joined units don't fit platforms (or guards cannot easily check tickets in both units).  My understanding is don't have selective door opening, it is front unit only and back unit not open, or all doors only.

Struggling to see how the allocations on the busy services will work, will it be 2 or 3 or 2+2 or 2+3 or 3+3 formations.

There was earlier comment about lack of 5car formations on Portsmouth-Cardiff.  Currently GWR have 41 class 158 vehicles, most are 2car, there is one 3car unit, and 4 units bodged into 3car made up from 6 2car units (so middle vehicle has a driving cab).  Clearly 41 vehicles is not enough to operate 8 trains of 5 vehicles and have spares for maintenance.   As they are about 35 years old scheduling them at nearly 100% usage is never going to be reliable, so realistically about 2 in 8 Portsmouth-Cardiff services are always going to have unsuitable stock (even after 175s cascade trains)

So short term that leaves the 165 units (built for branch lines and local suburban workings), but often used by GWR on long services to places like Worcester, Weymouth etc.  Again hardly in the suitable train type category on these extended workings. At least they have had a refresh, which partly hides their 33 years old age.

Then there are the 166s, all 3car, and often used as single units even on the quasi-intercity Cardiff-Portsmouth service (a route that serves 7 cities, a rather higher number than some mainline services).  But a 166 was never built and specified as a regional train, it was (and still is as seating has never been reconfigured) an outer suburban commuter train.  These days seem to be used randomly as common fleet with 165s (rather than being dedicated to the longer workings).  Actually not uncommon to see a 165 and 166 coupled.  Basically these are 32 year old hand-me-downs

Then GWR have the (now split at Exeter) Cardiff-South West workings.  Logically they would have identical fleet to Cardiff-Portsmouth.  But no, GWR has opted for 5car IETs (not because they are ideal, but because it is all that could be spared).  And yes they can at least run on electric Cardiff-Patchway (unlike the Cardiff-Portsmouth services which use old emissions spec diesel throughout, even though Cardiff-Patchway and Redbridge-Portsmouth are electrified).  Again questionable if they are suitable type, or simply spare hand-me-downs.

As for using IETs on some Bristol-Worcester services, don't get me started as to why GWR have ended up with so many 5car IETs instead of full length ones, but having got them (and abandoned the splitting of services they were ordered for, because software too slow to reconfigure during coupling/uncoupling) need to utilise the excess quantity of short IETs somewhere.   

Off record, personally wouldn't be too sorry if over half the 5car IETs were returned to leasing companies (and there are plenty of more suitable services around the UK that could use them better) and GWR ordered some comfortable 110-125mph battery EMUs for services to Oxford, Bedwyn, Warminster, Frome, Gloucester etc.

 
Hmm - On a regional journey of just over the hour, 1x5car IET or 2x3car 175s?

 

I think this is the key. A 5-car IET has 290 standard class seats whereas a 3-car 175 has 189. For many of the services 175s will be used on, 189 is more than enough, and an IET is overkill. So I suspect we'll see a train-for-train swap in many cases rather than a carriage-for-carriage swap.

All of that means there should be enough to send the HSTs to the scrapyard (or Mexico); cascade the 158s out of Devon & Cornwall for more capacity around Bristol and on Cardiff–Portsmouth; introduce a bit more slack into the Sprinter and Turbo fleets to cover for parts issues; and return IETs to the duties they were built for. I'd like to hope there'll be four IETs left after all that to run an hourly Oxford–Bristol, but time will tell.

 

This is not a new issue.  My son lived in Bristol and commuted to work in Yate by bike.  When he had evening meetings he would catch the train home; except for the days when the normal train was replaced by an HST and, since he had not reserved a bike space, he was prevented from boarding.  Why couldn't GWR recognise that bike reservations were not normally required and allow him plus bike on the replacement? 

 
A lot of good intentions are projected from GWR / GBR / DfT / NR but to me so much of the net results will depend on how it's implemented.

26 trains arriving totalling 68 carriages.

We know that some will replace the Castle sets - 3 of those left, perhaps, 12 carriages.  And I hear talk of withdrawal of some class 150 units - GWR operate 20 of these, 2 carriages each, so totalling 40 carriages.  If "Some" turned to "all", that would be 52 out of the 68 carriages spoken for.   That leaves - what - 15 carriages extra, or 3 x 5 car IET to be returned to working on lines to(wards) London.   Not quite that simple, perhaps - I'm nt convinced that 5 car IETs are needed on the local services at Ashchurch, so there could be a couple of other carriage released there, and I'm not sure whether a couple of branches such as Looe could actually be operated by any thing except 150s, so perhaps they are not all going?

 
GWR seems to have 3-5 DMUs semi-permanently out of use (due to lack of spare parts).   Being 33-36 years old they should really be withdrawing handful and parting them out to provide spares to keep the others running.   But although that is to some extent happening in practice with parts being 'borrowed' no one seems to have the guts to do it formally as it will leave shortage of trains on paper (not enough to cover all scheduled workings and allow normal number of maintenance spares).

GWR uses about 4-5 IETs on former Castle HST Cardiff-Plymouth services (now split at Exeter) and couple on Bristol-Worcester services (this was presumably what @simonw experienced) This is simply due to lack of anything else, doesn't mean they are best choice.  Also has direct result that a number of mainline IET services are often short formed as 5car instead of the booked 9 or 10car

The arrival of the 26 class 175 units (10 2car, 16 3car totalling 78 vehicles) to Devon and Cornwall will free up some 158, 165 units to Bristol area (timescale is vague, but in drips and drabs over next 10-20 months). The first ones with GWR need to cover the expanded Cornwall metro, then next ones replace the remaining aging Castle HSTs, so probably be 2026 before Bristol area sees an improvement.

I think the idea is that the IETs go back to mainline duties, and Bristol area locals make do with the old DMUs until 2029-2031 when (currently unauthorised and just an aspiration) replacements under project Churchward might arrive.

GWR has never had any regional trains in its fleet, it only has suburban/local trains and intercity style IETs (nothing between).  Technically could argue the 158s are regional, and 166s outer suburban, but as they seem to be used interchangeably they are effectively all same type.  There aren't enough 158s or 166s to be dedicated to regional services.

The result is get GWR suburban fleet doing 3+ hour journeys with no real passenger comfort and ambience, and IETs doing services under 2 hours with catering closed (and excess of First class).   Hopefully their new fleet will be 2 types, regional (which they desperately need) and local trains (South West trains did this with 444, 450, many common parts, but different bodyshells and configuration).  But GWR might try and do a single compromise standard type that fits neither role perfectly, have to wait and see. 

In an ideal world GWR would get battery BEMUs (dual voltage) for its long regional services, with seating designed for 3+ hour journeys, and able to cope with churn (lots getting on and off) at places like Bath.  With other features like 915mm level boarding and working air conditioning whose temperature is identical in all coaches. 5 or 6cars for the regional trains (no shorter) and 3car for local/suburban version (no 2car units).  And platforms extended to 6car length.  I can dream.
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Yesterday I was very surprised to board a GWR IET train at Aschurch (Tewkesbury)  for a stopping service to Bristol.

Stops at Cam&Dursley and then Yate required passwengers to move down to ther first three carriages.

Is GWR short of spare local train sets, or does it have spare IET's that it needs to use occasionally?