A 500-tonne crane has arrived in Oxford as Network Rail workers prepare for the mammoth task of replacing a bridge north of the city.

The giant crane has been unloading giant beams which will be used to construct a replacement of the Castle Mill stream bridge from tonight.

Manufactured in Ireland and delivered to the Oxford sidings north of the station over the past four days, these beams will be connected together this evening to create the new bridge.

Then an even bigger 750-tonne crane will be brought in to hoist the new bridge into place over Castle Mill stream.

The line will be closed from Wednesday, August 3 as the bridge is put in place and part of the track is replaced before re-opening the following Monday.

Network Rail town planner Guy Gibson said the current bridge's life had "expired" in a letter to Oxford City Council.

He said: "The work aims to increase train service capacity and improve journey time through Oxford.

"Current scheme proposals include electrification of all lines carried by the existing underbridge and a speed increase.

"The existing underbridge is life expired with the existing superstructure unable to accommodate the proposed line speed increases."

He added that the 20th century steel bridge had minimal architectural and historic interest.

The work is part of a number of improvement projects over the next two weeks which will see several key routes in and out of the city closed.

Routes linking Oxford to Didcot Parkway, Banbury, and Hanborough will all be closed as well as services between Bicester and Banbury.