The 38 class design based on a need to eliminate the complications of double heading required on a number of fast interstate passenger trains. The conditions of track work with frequent sharp curvature to be traversed at high speed would require six-coupled driving wheels in a ‘Pacific’ 4-6-2 configuration.

Maintenance considerations suggested a two-cylinder simple steam locomotive. In May 1939 an order for five 38 class locomotives was placed with Clyde Engineering with a distinctive streamlined boiler casing. The remaining 25 locomotives were built without streamlining at the NSWGR’s Eveleigh and Cardiff Workshops. From 1961 the locomotives were progressively withdrawn from service. Four have survived into preservation being 3801, 3813, 3820 and 3830.