So when additional branch line locomotives were required, the VR produced a 2-8-2 "Mikado" variant of the K, the first 2-8-2 tender engine in Australia.

However, production of the fourth batch ceased in 1951, after only three had been built, because the VR opted to order more of a new design of 2-8-0 branch line locomotive, the J class.

The VR sold ten of the North British-built N class locomotives (461, 465, 471, 474, 477, 485, 490, 491, 494 and 495)[5] to the South Australian Railways, which was experiencing a severe motive power shortage.

It travelled 6,000 miles (9,700 km) throughout Victoria from 1 February to 30 June 1951, visiting 168 stations and attracting 548,000 people to inspect its onboard exhibits.

[7] The ten N class locomotives sold to the South Australian Railways saw service on lightly built lines branching from Tailem Bend into the Murray Mallee.

The VR also modified the design of the Delta trailing truck on the second (1930-31 built) batch of N class locomotives to enable easy retrofitting of booster engines.

The post-war N class locomotives had a revised boiler design featuring a combustion chamber firebox and thermic syphons.

[10] The final batch of three Newport-built locomotives had a further evolution of the design, with German "Witte"-style smoke deflectors, and boxpok wheels.

With industrial action in the late 1940s threatening black coal supplies,[11] the VR began to convert the class to burn fuel oil, commencing with N 460 in September 1951.

[4] The final run of the class was in October 1966, when N 468 and N 475 hauled an Australian Railway Historical Society special passenger train.

752 (originally VR N 477), withdrawn after a service life of 262,593 miles (422,602 km), is preserved at the National Railway Museum, Port Adelaide.