Passengers using rail services through Newtown, Welshpool, and Caersws are being urged to plan ahead next month as engineering works lead to temporary changes across the network.
Network Rail will carry out infrastructure improvements on the Cambrian line between Shrewsbury, Aberystwyth and Machynlleth from Friday, May 8 until Friday, May 22.
Services between Llandrindod, Hereford and Shrewsbury will also be affected over the weekend of May 9 and 10.
The work is part of preparations for the introduction of new Class 197 trains on the Cambrian line later this year, alongside wider efforts to maintain a safe and reliable railway.
The programme includes track renewal at Montgomery, level crossing upgrades at Llanidloes Road in Newtown as well as Caersws and Llanbadarn Fawr, and bridge refurbishment in Shrewsbury. Land, drainage and vegetation work will also take place at several locations including Dol-y-Bont and Fronfraith.
Gwyn Rees, Programme Director at Network Rail Wales and Borders, said: “These essential upgrades will help us maintain a safe and reliable railway for passengers and freight services across mid Wales and the Borders. We’ve carefully planned this work to minimise disruption, wherever possible, with the line due to fully reopen in time for the May half term.
“We’d like to thank passengers for their patience while we carry out these important improvements.”
Transport for Wales said rail replacement buses will operate during the works, including dedicated services for schools and colleges along affected routes.
Colin Lea, Planning and Performance Director at Transport for Wales, said: “We know this will be a disruptive period for customers travelling across mid Wales and the borders, and we’d like to thank everyone for their patience while these essential improvements are carried out.
“With different sections of the railway closed on different days between 8 and 22 May, it’s really important that customers travelling between Aberystwyth, Pwllheli, Shrewsbury, Hereford and Llandrindod plan ahead and check their journey before travelling, using our website or app.
“These upgrades are a vital step towards introducing our brand-new Class 197 trains on the Cambrian line later this year, which will bring improved comfort and capacity for customers.”
The line is expected to fully reopen ahead of the May half term.