No GWR trains from Reading into Paddington on 28-29 November or from Christmas Day to 3 January while Dolphin Junction is rebuilt. Waterloo is the way in.

GWR trains will not run between Reading and London Paddington on the weekend of 28 and 29 November, or from Christmas Day to Sunday 3 January, while Network Rail rebuilds Dolphin Junction in Slough. Network Rail confirmed the dates today and put the cost of the upgrade at £27.8 million (Network Rail, 14 October 2026).

During both closures GWR’s London trains will start and finish at Reading, or run on a diversion to London Euston. GWR services go back into Paddington on Monday 4 January. Journey planners have now been updated with the changes up to 4 January, so Christmas trips can be booked and checked now.

The quick answer

  • 28 and 29 November: no GWR trains into Paddington. A fast GWR service will run between Reading and Guildford to connect with South Western Railway to Waterloo.
  • 25 December to 3 January: the main closure. From 27 to 30 December there are no GWR or Elizabeth line trains between Reading and Paddington; South Western Railway runs Reading to Waterloo.
  • The Euston diversion does not stop at Reading. National Rail says passengers cannot use those trains at Oxford, Didcot Parkway or Reading.
  • 4 January: GWR is back into Paddington.

What is being done

Network Rail says it is replacing ageing points, improving the track layout and upgrading the overhead line equipment at the junction, with new track as well and a deep clean of Paddington station. About 400 passenger trains carrying more than 100,000 passengers go through Dolphin Junction every day, it says, which makes it one of the busiest pieces of railway on the Great Western Main Line.

Engineers in orange high-visibility clothing work beside the track at night under floodlights, with a crane lifting a steel gantry for the overhead wires.
Overhead line equipment work at night on the Great Western Main Line. Photo: supplied by Network Rail.

Ross Mahoney, project director for Network Rail’s Great Western route, said:

“Dolphin Junction is one of the busiest and most important parts of the Great Western Main Line, carrying thousands of passengers every day between London, the Thames Valley, the South West and Wales.

“This investment will replace ageing equipment with modern technology and improve the track layout, helping trains move through the junction more smoothly and efficiently. This will mean less congestion and more reliable journeys for passengers across the route.”

The November weekend is preparation for the main Christmas work, which Network Rail says will reduce overall disruption. The project is part of a wider programme of engineering work across the Thames Valley over Christmas and New Year, and follows the Thames Valley Performance Improvement Programme.

The two closures, day by day

Timeline of the Reading to London rail closures: Saturday 28 and Sunday 29 November no GWR trains to Paddington, with fast GWR trains from Reading to Guildford for SWR to Waterloo; 25 and 26 December the usual Christmas shutdown; Sunday 27 to Wednesday 30 December no GWR or Elizabeth line trains between Reading and Paddington, SWR runs Reading to Waterloo; Thursday 31 December to Sunday 3 January the Elizabeth line and Heathrow Express start returning but no GWR trains into Paddington; Monday 4 January GWR trains run into Paddington again.
When the trains from Reading into London are affected. Graphic by Reading Daily.
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The detail below comes from National Rail’s Dolphin Junction upgrade page, checked on 14 October 2026.

Saturday 28 and Sunday 29 November

  • GWR trains cannot run to or from Paddington. Most long-distance trains will start and end at Reading. Bristol and South Wales trains will be diverted between Swindon and Euston.
  • A special fast GWR service will run each way between Reading and Guildford, connecting with South Western Railway trains between Guildford and Waterloo.
  • The direct trains from Reading to Waterloo are expected to be extremely busy because of international rugby at Twickenham that weekend.
  • The Elizabeth line will run only between Reading and Maidenhead. Beyond that, buses replace trains between Maidenhead and Slough and between Slough and Ealing Broadway, with the Underground on to central London.
  • There will be no Elizabeth line or Heathrow Express trains to Heathrow. The Piccadilly line will be the only train to the airport from central London.

Sunday 27 December to Sunday 3 January

Network Rail’s release dates the main phase from Christmas Day; there are no trains anywhere on Christmas Day and most of the railway is shut on Boxing Day in any case. Then:

  • 27 to 30 December: no Elizabeth line trains between Reading and Paddington and no GWR trains between Paddington and Slough. South Western Railway runs between Reading and Waterloo, and National Rail warns those trains may be extremely busy on Monday 28 December, again because of rugby at Twickenham. There will also be engineering work elsewhere on the SWR network.
  • 31 December to 2 January: GWR trains run between Reading and Slough. The Elizabeth line does not run between Reading and Hayes & Harlington, so replacement buses cover Slough to Hayes & Harlington.
  • 3 January: GWR trains run between Reading and Maidenhead, with buses from Maidenhead to Hayes & Harlington.
  • Elizabeth line and Heathrow Express trains to Heathrow stop until 30 December and start again on New Year’s Eve.
  • Chiltern Railways runs from Marylebone to Oxford, High Wycombe and Banbury throughout, with changes at Oxford for Reading.
Network Rail poster with a cartoon dolphin in a hard hat holding a spanner, reading: We're upgrading the hardest-working dolphin in the Thames Valley. Every day more than 400 trains and 100,000 passengers pass through the junction.
The railway's poster for the Dolphin Junction closures. Photo: supplied by Network Rail.

What GWR says

Richard Rowland, GWR’s operations director, said:

“Our priority over Christmas is making sure customers can still get where they need to go.

“Although trains won’t run into London Paddington for a short period, we’ve worked closely with Network Rail and our industry partners to put alternative routes in place, including GWR services from London Euston, and connections via Waterloo and Marylebone.

“This does however mean some journeys may take longer than usual; so we ask anyone travelling to or from London during this period to plan ahead and check before they travel. Our teams will be on hand to help customers along the way.”

Mr Mahoney added: “We know this work will cause disruption in the short term, and we’d like to thank passengers and freight customers for their patience. Once complete, these upgrades will help create a more dependable railway, supporting better performance and smoother journeys for years to come.”

What it means for you

  • Going to London from Reading on those dates: plan on South Western Railway to Waterloo, or on the 28 and 29 November weekend the GWR fast train to Guildford and SWR from there. Allow longer than usual, and expect crowds on 28 and 29 November and on 28 December.
  • Flying from Heathrow between 27 and 30 December: no Elizabeth line or Heathrow Express train runs to the airport. Check before you book a rail route.
  • Coming back from the West Country or Wales: most trains will end at Reading. The Euston diversion trains do not call at Reading, so they are not a way home.
  • Check the train you want on GWR’s planned engineering page or any journey planner, which now carry the changes up to 4 January.

For the rest of the holiday on the railway and buses, see Reading Christmas trains and travel, and for normal fares and times, Reading train times to London. Road closures are on Reading roadworks and travel.