weekend.Chiltern Railways will be carrying out track improvement work on Saturday and Sunday (March 16 and 17).The line will be closed on both days and rail replacement buses will be in service between the two stations. An amended timetable will run between Marylebone and Birmingham. Journey times will be extended.A normal service will operate on the Marylebone – Amersham – Aylesbury Vale Parkway and Marylebone – Oxford routes.A spokesman said: “We advise that customers plan in advance allowing additional time for their journey and check before they travel.”We also recommend purchasing tickets in advance via our website or app to save time at stations and guarantee the best prices.”