Contractor Buckingham Group can now start work on the new station, which will be built just to the north of the existing station.
The firm will also install a footbridge, shops, a travel centre, first class lounge and customer reception.
It will connect to the new 900 space multi-storey car park at the Merchant Gate development.
Phil Verster of Network Rail, said: “Whilst the old station is undoubtedly a striking building, passengers at Westgate will be well aware that it is no longer fit for purpose.
“By moving passenger facilities to a new purpose-built building we can improve the journey experience in a sensible, cost-efficient way. “