An introduction for newer members ... and a reminder for the rest of us

Great Western Railway (which is a trading name of First Great Western) are the train operator who provide franchised train services across routes from London via the Thames Valley to the South West of England, South East Wales and the Cotswolds and on other routes within and across those areas (together with a handful that spill out reaching destinations such as Brighton, Carmarthen and Gatwick Airport).  Full List below. Their operating contract is with the Department for Transport (and they may have supplementary contracts - for example with Devon Council for extra services) and is laid down in the "Service Level Commitment".  Version 3b of this was due to take effect in December 2018 but is now postponed to December 2019.

There has been discussion on the GWR^▸ (Great Western Railway) timetable that will be running from the end of this year across a number of our boards here - should members wish to read the details of what the service contract requires, it's available as part of a bundle on the DfT^» (Department for Transport - about)'s web site; for archive purposes and easy reference I have mirrored it ((here)). Note this document has been around a while - hence a couple of "if, then" cases to which we know the outcome already.  If there's an updated version / link, please post!

I have had some practise at reading documents like this over the years ... picking out some interesting ground rules which lead to an understanding of why certain services run as they do.  Comments very welcome - I will add some of my own in due course.

Routes covered ...

Great Western Main Line
A1 London Paddington – Reading – Swindon.
A2 London Paddington – Cardiff Central – Swansea.
A3a London Paddington– Bath Spa - Bristol Temple Meads/Weston super Mare
A3b London Paddington - Bristol Parkway - Bristol Temple Meads/Weston super Mare
A4 London Paddington/Swindon - Cheltenham Spa

West of England
B London Paddington – Plymouth / Penzance

Thames Valley Inner
C1^▸ ((on coaches) National route restriction) London Paddington – Reading (dated)
C3 West Ealing – Greenford
C4 Slough – Windsor & Eton Central
C5 Maidenhead – Marlow
C6 Twyford – Henley-on-Thames

Thames Valley Outer
D1 London Paddington – Oxford (Fast services)
D2 Reading – Oxford
D4 Oxford – Banbury
D5 Oxford – Worcester Foregate Street - Hereford
D6 London Paddington – Reading – Newbury – Bedwyn
D7 Reading – Basingstoke

North Downs
E Reading – Redhill / Gatwick Airport

Regional Interurban
F1 Cardiff Central – Portsmouth Harbour
F2a Cardiff Central – Bristol Temple Meads
F2b Bristol Temple Meads – Westbury
F3 Westbury – Southampton Central
F4 Westbury – Weymouth
F5 Westbury – Swindon
F6 Southampton Central – Brighton

Bristol
G1a Bristol Temple Meads – Taunton – Exeter St David’s
G1b Bristol Temple Meads – Weston super Mare
G1c Bristol Parkway – Bristol Temple Meads
G2 Bristol Temple Meads – Severn Beach
G3 Bristol Temple Meads – Cheltenham Spa - Great Malvern

Devon and Cornwall
H1 Exeter St David’s – Plymouth
H2 Plymouth – Penzance
H3 Exeter St David’s – Exmouth
H4 Exeter St David’s – Paignton
H5 Exeter St David’s – Barnstaple
H6 Exeter Central – Crediton
H7 Plymouth – Gunnislake
H8 Liskeard – Looe
H9 Par – Newquay
H10 Truro – Falmouth Docks
H11 St Erth – St Ives

The phrase "Services may be joined with services specified in Route C1^▸ ((on coaches) National route restriction) to provide through services." (my bolding) appears the same in the 3b version as it does in the current one, ie through running between these services is permitted by the operator but is not a requirement.

There have been suggestions (leaks?) that GWR^▸ (Great Western Railway) is willing to negotiate away to TfL^» (Transport for London - about) the requirement to run more of the C1 services than anticipated by the 3b document, which wouldn't be a conflict but further balkanise the service provision.

I have heard a rumour that GWR^▸ (Great Western Railway) will attempt to stop direct services from London to Nailsea, Yatton, and Weston with all services changing at Bristol. Is this possible under their contract?

As Graham says, it would only be possible if the Government alters the SLC^▸ (Service Level Commitment) (Service Level Commitment) for the new franchise.  I think that's very unlikely.  The draft December 2019 timetables have several through trains as they do now, though (IIRC^▸ (if I recall/remember/read correctly)) one less each way.  Many of them are speeded up quite considerably though - Paddington to Weston-S-M in 1 hour 50 mins is likely to feature, some 30 minutes quicker than currently!

There were always going to be bi-modes, the 5-car units, as part of the fleet to supplement the 9-car electric trains, so Weston would still have kept its through trains.

Thank you all for the very useful and clear replies.