The Office of Rail and Road (ORR) has approved a plan to improve train reliability and punctuality in Wales and western England.
This region includes some of the busiest UK routes to and from London Paddington.
The plan, created by Network Rail, addresses underlying issues that had led to poor train performance in the Wales and Western region.
The ORR had previously found that Network Rail was not doing all it could to enhance train performance for both passengers and freight.
The original proposals by Network Rail, including the Thames Valley performance improvement plan, lacked detail, timelines, and breadth to ensure lasting improvements.
However, in response to the ORR's investigation, Network Rail and the Wales and Western region, led by Rob Cairns, drafted a comprehensive performance plan.
This plan, which includes nearly 60 individual actions, has now been accepted by the ORR.
The ORR will monitor the delivery of the plan, with 90 per cent of actions slated for completion by 2026.
Some actions, such as conducting exercises to improve response to stranded trains and changing governance to focus on train punctuality and reliability, are expected to be implemented before the end of the year.
The plan covers several areas, including timetable resilience, forecasting extreme weather events, asset reliability and performance, performance leadership, behaviours and accountability, learning from past and future disruption events, and increased collaboration between industry bodies, including train operators.
Feras Alshaker, director of performance and planning at ORR, said: "We are pleased with the detailed work Network Rail has done to create a clear, workable plan that should sort out the underlying issues and deliver sustained improvement for passengers.
"Passenger train performance in the Wales and Western region has been letting customers down for too long.
"We pushed for this plan to be comprehensive and region-wide, and it is.
"We will be watching to make sure Network Rail delivers on its promises to passengers."
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