Passengers expecting to travel on the railways in Somerset and beyond on Monday, May 25 and Tuesday, May 26 will face delays and cancelled services as a strike goes ahead.

Services are expected to be significantly affected from Midnight on Sunday, May 24 through until Tuesday, May 26 and in the morning of Wednesday, May 27.

RMT and TSSA trade union members employed by Network Rail have voted in favour of taking industrial action

Network Rail has confirmed that they do not expect to be able to allow access to the following areas of the First Great Western network, and no trains will run after 0001 Monday 25 May and Tuesday 26 May. Service start up on Wednesday will also be affected:

• Between Reading and Taunton

• Beyond Plymouth to Penzance and on Devon and Cornwall branch line services

• Reading to Gatwick Airport/Reading to Basingstoke

It is unlikely seat reservations will be honoured on these days, but should travel plans be altered y the reservation can be changed without penalty.

A spokesman said: "We have been talking to Network Rail about the planned strike and the impact on First Great Western services. Should action go ahead is it likely to have a significant impact on our ability to run our train services throughout this period. Trains that are able to run are expected to be busy.

"Full refunds will be available for customers who have already bought tickets during the industrial action period and choose not to travel, and Season Ticket holders will be compensated for any days affected.

"Those with tickets for travel on Monday and Tuesday will also be able to use their ticket to travel on Sunday 24 May or Wednesday 27 May, subject to any travel restrictions that would normally apply to your ticket.

"If you have an Advance Purchase ticket for Monday or Tuesday you will also able to travel on Sunday or Wednesday using the same service or one immediately before or after the booked time.

During Monday and Tuesday it is expected that services will operate at a reduced service frequency between 0730 and approximately 1830; please check timetables on the day for details of your last service.

Subject to agreement from Network Rail, the following services will run

• Cardiff – Taunton, calling at Newport, Severn Tunnel Juncton, Patchway, Filton Abbey Wood, Bristol Temple Meads, Nailsea, Yatton, Worle, Weston-Super-Mare, Highbridge, Bridgwater and Taunton: Hourly Devon and Cornwall

•Paddington – Plymouth, calling at Reading, Bristol Parkway, Bristol Temple Meads, Taunton, Tiverton, Exeter, Dawlish, Teignmouth, Newton Abbot, Totnes, Ivybridge (select trains only) and Plymouth: Hourly

• Paddington – Bristol Temple Meads, calling at Reading Didcot, Swindon, Chippenham, Bath and Bristol, extended to Weston-Super-Mare and Taunton during peak: Hourly

•Paddington – Didcot, calling at Slough Maidenhead (Peak only) and Reading: Every 30 mins

•Paddington – Didcot, calling at Ealing Broadway, Southall Hayes and Harlington, West Drayton, Iver, Langley, Slough, Maidenhead, Twyford, Reading, Tilehurst, Pangbourne, Goring and Streatley, Cholsey and Didcot Parkway: Every 30 mins

•Paddington – Reading non-stop to operate during peak time only: Every 30 mins

•Paddington – Reading, calling at Acton Mainline, Ealing Broadway, West Ealing, Hanwell, Southall, Hayes and Harlington, West Drayton, Slough, Burnham, Taplow, Maidenhead, Twyford and Reading: Every 30 mins

• Branch line services to Bourne End/Marlow and Windsor to run every 20/30 mins Bristol

• Swindon – Bristol, calling at Chippenham, Bath Spa, Oldfield Park, Keynsham, Bristol Temple Meads: Hourly

•Bristol Parkway – Weston-Super-Mare, calling at Filton, Stapleton Road, Lawrence Hill, Bristol Temple Meads, Bedminster, Parson St, Nailsea and Backwell, Yatton, Worle, Weston Milton and Weston-Super-Mare: Hourly South Wales

•Paddington – Swansea on Monday and Cardiff on Tuesday, calling at Reading, Didcot Parkway, Swindon, Bristol Parkway, Newport and Cardiff: Hourly

• Exeter – Newton Abbot, stopping service: Hourly

• Sleeper services will not be able to operate on Sunday, Monday or Tuesday.