The business case had taken 18 months to produce .
The business case was created by representatives from Network Rail , Birmingham City Council , Advantage West Midlands , and the West Midlands Passenger Transport Authority ( WMPTA ) .
The business case had taken 18 months to produce and was created by representatives from Network Rail , Birmingham City Council , Advantage West Midlands , and the West Midlands Passenger Transport Authority ( WMPTA ) .