This was intended to reduce maintenance costs and repair downtime, and was achieved by designing five new classes of locomotive - Main line passenger and goods, light lines passenger and goods, and suburban tank engines - which shared among them as many components as possible, reducing the range and quantity of spare parts required and allowing engines undergoing repair to swap out components as needed.

"[2] Using the range of designs provided by Jeffreys, of the Monkbridge Iron and Steel Company of Leeds, twenty D Class engines were constructed at Phoenix Foundry, with builders numbers 200 to 219, entering service in 1887 and 1888.

New features included a drop-door for the firebox in lieu of the older sliding door type, which became the default for all locomotives built over the following forty years, a double-ended regulator handle, and the leading bogie was noted as an "outside frame swing link type with equalisers between the springs, much more suitable for passenger service than the Bissel truck of the Beyer, Peacock 4-4-0s.

Cave, et al. notes that in the early 1890s, common duties were on the main Gippsland line and double-heading on the Adelaide Express, and that in 1894, "two were allocated to Bendigo, three to Ballarat, five to Stawell, one to Geelong [working Queenscliff branch and Colac mixed services] and nine to the Princes Bridge depot in Melbourne".

[3] Engine 122 was sold to the Kerang-Koondrook tramway in 1920 and remained in service on that line until after it was re-absorbed into the Victorian Railways fleet, finally being scrapped in January 1952.