the d class (later reclassified into d, d and d subclasses) was a passenger and mixed traffic steam locomotive that ran on victorian railways from 1902 to 1974. originally introduced on mainline express passenger services, they were quickly superseded by the much larger a class and were relegated to secondary and branch line passenger and goods service, where they gave excellent service for the next fifty years. the d design was adapted into a 4-6-2t tank locomotive for suburban passenger use, the d (later d) class. they were the most numerous locomotive class on the vr, with a total of 261 d and 58 formula_1 locomotives built.