Reclassified as the 35 class during the 1924 renumbering program, these locomotives were originally known as the NN class, which gave rise to the nickname ‘Nanny’. Built in 1917, 3526’s original number was 1314.  

The 35 class 4-6-0 locomotives were built by the NSW Government Railways (NSWGR) at their workshops at Eveleigh. Coincidentally, there were 35 engines in the 35 class. They were intended to reduce the amount of 'double-heading' required for main line express trains following the introduction of heavy, twelve-wheeled corridor compartment cars.  

Teething problems with the new design were overcome by several modifications throughout their service (including re-framing and re-balancing the driving wheels), seeing them develop into solid performers. The original cabs were replaced to provide the crew greater protection against the weather.   

With the advent of the 36 and later the 38 classes, the 35s spent the greater part of their lives on northern services. 3526 is one of the few NSW locomotives to have been painted in blue livery for a time, while hauling the Caves Express services from Sydney to Mount Victoria in the 1930s.