The plan included three new stations, at Quex Road, Kilburn Park Road and Clifton Road, but did not progress after Ministry of Transport revised its Requirements for Passenger Lines requiring a means of exit in an emergency at the ends of trains running in deep-level tubes – compartment stock used north of Harrow did not comply with this requirement.
Planen indeholdte tre nye stationer, ved Quex Road, Kilburn Park Road og Clifton Road, men blev ikke ført videre efter Transportministeriet reviderede sine krav til passagerjernbaner, der nu krævede en nødudgang i togets ender, for tog der skulle køre i dybtliggende tubes – kupémateriellet, der blev benyttet nord for Harrow, levede ikke op til dette krav.