Rail bosses say £2m. improvements to the line between Burnley and Colne are on track.
Network Rail engineers are working to upgrade a 1.5 mile section of track between Rosegrove and Brierfield.
Work is currently being carried out on the Victorian-era viaduct in Burnley before maintenance starts on a 2.3 mile stretch of railway between Brierfield and Colne.
A nine-day closure of the line has been in place with replacement bus services for passengers travelling from Colne and Rosegrove calling at Burnley Barracks, Burnley Central, Brierfield and Nelson expected until Sunday.
Rail chiefs say the improvements will reduce the need for future maintenance and provide a more reliable service for passengers in East Lancashire.
Martin Frobisher, area director for Network Rail, said: “This work will provide an improved railway along the section of line between Colne and Rosegrove which will be more reliable and require less maintenance, helping us provide a safe and efficient railway.
“It is a significant piece of engineering which can only be carried out while the railway is closed. We have worked closely with Northern Rail to plan the work so we can complete it as quickly and safely as possible and apologise for the disruption the work will cause.”
Existing track is being replaced by new continuous lengths of rail which bosses say will make journeys smoother and quieter.
Work is being carried out to upgrade lighting at Brierfield Station as well as the town’s level crossing.
Network Rail is also planning to enhance stations, cut back vegetation and remove litter and graffiti along the stretch of track when the line reopens.