No. 17 of the Wellington & Manawatu was the third Mikado tender locomotive ever built. Baldwin created it in 1901 and directly based it on the two Japanese Bt4/6 which had been the first Mikados and later became known as JGR class 9700. At the same time, Baldwin also built the NZR class Q Pacifics. Both had a similar design of trailing axle that carried a wide firebox. They were the biggest and most powerful locomotives of their time in New Zealand.
In contrast to the Q, No. 17 was a four-cylinder Vauclain compound with all cylinders on the outside, where the low pressure cylinders were above the high pressure ones. It was able to haul 280 tons over the challenging WMR main line with inclines of 1 in 56 or 1.8 percent. In 1908, when the WMR became part of the NZR, the locomotive became class BC No. 463. It was withdrawn in 1927, remaining the only Mikado in New Zealand.