Engineering works cause disruption to rail services between Didcot Parkway and Oxford
Emergency engineering work has seen Great Western Railway trains cancelled between Oxford and Didcot Parkway - and Cross Country trains between Oxford and Reading.
It is because urgent repairs have been needed to a bridge.
The work is expected until the end of Monday (3 April), with train companies urging commuters to check before they travel.
On the company's website GWR said: "While we are unable to run trains limited Rail Replacement Transport is in operation between Didcot Parkway and Oxford, some services will run direct between the two and some will call at Appleford, Culham and Radley.
"Please wait at the appropriate bus pick up point shown on the Onward Travel Information posters.
"The replacement transport may not be running at the same time as trains and journeys on this replacement transport will take longer."
Elsewhere, engineering works over Easter weekend will also see buses replace trains from Friday 7 until Monday 10 between Reading and Andover, as well as between Woking, Winchester and Andover.
South Western Railway is urging passengers to plan ahead, as some train services could start and end at different stations.
Rail users can find out more about the work and replacement services here.