Passengers are urged to check before they travel between Machynlleth and Pwllheli next month, when Network Rail will be carrying out essential engineering work on the Cambrian Line.
Network Rail engineers will be replacing more than 1km of track between Dyffryn Ardudwy and Harlech stations.
They will install 1,800 new sleepers and 3,600 tonnes of ballast (track stone) using an auto hopper train which will be refilled from a virtual quarry at Marine Parade, Barmouth.
Nick Millington, Network Rail Wales and Borders route director, said: “Our teams will be working around the clock to carry out this important track renewal on the Cambrian Line. The age of the track and its exposed location on the Cambrian Coast means we must replace it this winter.
“We recognise there is never a good time to close the railway for more than a week. But this allows us to minimise wider disruption and do the work in a more cost-effective way than if we had to return over several weekend shifts.
“I would like to thank passengers for their patience and understanding and urge them to check their journeys before travelling.”
Transport for Wales (TfW) will run a mixture of fast and stopping buses.
On Sunday 8 December, the 16:52 and 18:55 Machynlleth to Pwllheli services will be replaced by buses.
From Monday 9 December and Sunday 15 December, buses will replace trains all day.
On Monday 16 December, the 06:29 and 07:29 Pwllheli to Machynlleth services will be replaced by buses.
These replacement buses will run earlier than usual to connect with train services at Machynlleth.
Details are available in journey planners on the Transport for Wales website and passengers are strongly advised to check for the latest information before travelling.
Image credit: Network Rail