Rail upgrades and repair work in West Yorkshire are set to impact passenger journeys for two consecutive weekends, Network Rail said.
Track renewal, tunnel repairs and groundwork engineering is taking place on Saturday 18 and Sunday 19 July in the Menston area, with the project continuing next weekend between 25-26 July.
Some disruption to railway trips around Bradford, Leeds, Ilkley, Shipley and Frizinghall is expected during the works.
Buses replace trains between Ilkley and Shipley on Saturday 18 July and on Saturday 25 July, Network Rail said.
On Sunday 19 July and Sunday 26 July, LNER trains usually starting or terminating at Bradford Forster Square will instead start and terminate in Leeds.
Northern will have rail replacement buses between Bradford Forster Square and Shipley/Ilkley.
In addition:
New rails and sleepers will be installed along about 1.9km of the line, the firm said, to make future journeys “smoother and more reliable”.
Brick and stonework repairs will take place in the Esholt Tunnel to keep it “in sound condition” and avoid future maintenance issues.
Network Rail operations director Karen Duffy said the work was “essential” to keep the railway safe.
“We’re sorry to anyone whose journey is affected and grateful to passengers and residents for their patience while we complete these upgrades, which will help deliver smoother and more dependable journeys in the future,” Duffy said.
LNER and Northern said people should check before travelling on these dates and allow extra time for journeys.
