While the early years of diesel operations on the New South Wales Railways had been a steep learning curve, the 44 Class marked an inflection point as one of the most successful in operation. Following the introduction of the 40, 41, 42 and 43 classes with varying technologies in quick succession, the NSW Government Railways were keen to implement a standardised class with the lessons it had learned.

In a marked departure from previous classes, their design was based on the Alco "World" model supplied by A E Goodwin, making them the first dual cab diesel locomotives introduced to operations. Their design featured a streamlined bulldog nose-like design at one end, and a flat cab on the other.

As a result, while earlier classes had been a sign of the incoming tide, the introduction of the 44 Class truly began the revolution marking the end of the steam era. During their operating lives, the versatile 44 Class operated on every type of train, from the austere Southern Aurora right down to goods services.

So effective were the 44 Class that the railways put in an additional order for 40 locomotives in 1967, bringing the class to 100-strong.