Mangaroa railway station war. After the war the depot was a disposal site for surplus stores until RNZAF use ceased in July 1949, at which time it is assumed that the site was transferred to the NZ Army for their use. Prior to the construction of the Rimutaka Tunnel, several proposals for a tunnel under the Rimutaka Ranges to bypass the Incline section involved tunnels with a western portal to the north-east of Mangaroa station. In 1898 a survey was completed for a tunnel between Mangaroa and Cross Creek. The idea received a great deal of attention, but ultimately went nowhere as such
Beaminster Tunnel a white cross which can still be seen "in situ". The tunnel reduced the road's gradient from 1-in-6 (17%) to 1-in-10 (10%) and shortened it by a mile (1.6 km), as well as lowering its maximum elevation by . At the time of its opening, only a handful of road tunnels had been built in Britain; it pre-dates the construction of the first railway tunnels, and it is now the only pre-railway road tunnel in the country still in use. The tunnel was formally opened on 29 June 1832 with enthusiastic celebrations including a 21-gun salute fired from the top