Chiltern Railways passengers are being urged to check before they travel ahead of a five-day closure of the main line between Bicester and Leamington Spa this month.

The closures is to allow Network Rail to complete "vital improvement works" at the end of the month, and will impact trains from south Warwickshire to London.

As part of a £9 million investment, Network Rail and its partners at Story Contracting will work around the clock between Saturday 27 and Wednesday 31 July to replace a bridge which carries the railway over the River Cherwell in King's Sutton near Banbury.

During the rail closure engineers will lift a new 240-tonne bridge deck into place using two special rail-mounted 'Kirow' cranes.

Once complete the work will keep the structure safe and reliable for passengers and freight services for decades to come, Network Rail said.

At the same time engineers will upgrade over 500 metres of railway north of Banbury station which includes replacing sections of track and drainage to help make journeys smoother.

While the work takes place the railway will be closed between Bicester and Leamington Spa stations.

Improvements will also be taking place this weekend.

The railway will be closed between Bicester and Dorridge before 10am on Sunday 21 July. In addition, the railway will be closed between Bicester and Leamington Spa all day on Sunday 21 July and rail replacement buses will be in operation.

Replacement buses will be in place between:

• Bicester Village - Banbury - Leamington Spa.
• Bicester Village - Banbury - Stratford Upon Avon.
• Bicester Village - Kings Sutton - Banbury.

Adam Checkley, infrastructure director for Network Rail, said: "I'd like to thank passengers for their patience while we complete over £9m of upgrades on the Chiltern main line between Bicester and Leamington Spa stations this month to help make journeys more reliable.

"If you're planning to catch a train during the rail closures, please check with Chiltern Railways and at www.nationalrail.co.uk before you travel for information about your journey."