Industrial action by the RMT, Aslef and the TSSA unions is set to severely affect trains across the GWR network this weekend and next week, with services unable to operate across many routes.

The action is planned for Saturday 13, Thursday 18 and Saturday 20 August, with days immediately after the strike days also affected.

A significantly reduced temporary timetable has been put in place.

Passengers are being advised to find alternative ways to travel on these days.

The message is: Only travel if absolutely necessary. The majority of train services will not operate and there will be no services on many routes.

On strike days an extremely limited service will operate between 0700 and 1830, and last trains will leave much earlier.

Where trains are able to operate, they will be extremely busy.

GWR has said it will operate as many trains as possible during the strike action, however the following travel advice is in place over the strike period:

Friday 12 August Trains will run as planned but will be busy, and with some minor changes to late night services. Please check before you travel including those travelling to the Boardmasters Festival.

Saturday 13 August An extremely limited service will only operate on the routes below. Services will start later and finish much earlier than normal.

Bristol Temple Meads-London Paddington; Reading to Oxford; Reading to Basingstoke

No other GWR services will run.

Sunday 14 August Trains will continue to be severely disrupted, especially on long-distance intercity routes, please make alternative travel arrangements and only travel if absolutely necessary. There will be no service on the Oxford to Worcester/Hereford route:

A reduced service frequency will operate on other long-distance routes:

London Paddington to Bristol Temple Meads

London Paddington to Swansea

London Paddington to Plymouth/Penzance (inc via the Kennet Valley)

London Paddington to Oxford

Local stopping services will operate. Please check before you travel.

Monday 15 August A normal timetable will operate.

Tuesday 16 August A normal timetable will operate.

Wednesday 17 August Trains will run as planned with some minor changes to late night services. Please check before you travel.

Thursday 18 August A significantly limited service will operate please make alternative travel arrangements and only travel if absolutely necessary. No rail services will operate on the following routes:

All lines in Cornwall, including all branch lines

West of Newton Abbot (change at Exeter) towards Plymouth/Cornwall (due to no contingency signallers)

All branch lines in Devon (Barnstaple, Exmouth, Paignton, Okehampton)

South Wales main line (Carmarthen/Swansea–Cardiff Central)

Berks & Hants line (Reading–Taunton via Castle Cary)

Wessex main line (Bath Spa–Portsmouth Harbour)

Heart of Wessex line (Westbury–Weymouth)

TransWilts line (Swindon–Westbury via Melksham)

Severn Beach line (Bristol Temple Meads–Severn Beach)

North Cotswolds line (Hereford/Worcester–Oxford)

South Cotswolds line (Cheltenham Spa–Swindon)

Worcester/Gloucester

Greenford branch line

North Downs line (Reading–Gatwick Airport)

Please check before you travel.

Friday 19 August Trains will continue to be disrupted, please make alternative travel arrangements and only travel if absolutely necessary. Trains will start later and there will be a reduced level of service throughout the day. Please check before you travel.

Saturday 20 August An extremely limited service will operate. Services will start later and finish much earlier than normal. No rail services will operate on the following routes:

Between Bristol Temple Meads to London Paddington

Between Cardiff and Bath

Between Bristol and Gloucester

Between Bristol and Exeter

All lines in Cornwall, including all branch lines

West of Newton Abbot (change at Exeter) towards Plymouth/Cornwall

All branch lines in Devon (Barnstaple, Exmouth, Paignton, Okehampton)

South Wales main line (Carmarthen/Swansea–Cardiff Central)

Berks & Hants line (Reading–Taunton via Castle Cary)

Wessex main line (Bath Spa–Portsmouth Harbour)

Heart of Wessex line (Westbury–Weymouth)

TransWilts line (Swindon–Westbury via Melksham)

Severn Beach line (Bristol Temple Meads–Severn Beach)

North Cotswolds line (Hereford/Worcester–Oxford)

South Cotswolds line (Cheltenham Spa–Swindon)

Worcester/Gloucester

Greenford branch line

North Downs line (Reading–Gatwick Airport)

Sunday 21 August Trains will start later, however a normal level of service is expected. Please check before you travel.

Customers who have already purchased tickets for strike days can claim a full refund or amend their ticket; those who travel and are delayed may be entitled to delay repay compensation if they are delayed by 15 minutes or more.

Season ticket holders can apply for compensation through the Delay Repay scheme.

Where the company can run trains, they are expected to be extremely busy. They are not able to provide bus replacement services.

To help customers, GWR is allowing people with tickets for travel on Saturday 13 August to be able to travel on the day before and up to and including Tuesday 16 August. People with tickets for travel on Thursday 18 and Saturday 20 can travel on the day before and up to and including Tuesday 23 August.

Those travelling during the latter half of this week are also being reminded of the weather forecast and advised to check their journeys and ensure they are well-prepared for the extreme conditions – wearing cool clothes, taking handheld fans and ensuring they have plenty of water to drink.

GWR’s refund policy and Book with Confidence policy remains in place. If you hold a return ticket, you can claim a refund of your unused full fare, even if only one leg of your journey is affected.