The X200 class were a group of rail tractors introduced in 1968 and operated by the New South Wales Government Railways of Australia. They were a development of the smaller and less numerous X100 class. The X200 class remained in NSWGR service until 1990 when they were either withdrawn or sold off to private companies, and many remain operational today.
The first series of the X200 class (now distinguished as the Mk.1 variant) were larger and more powerful, being 3 times more powerful and twice as heavy as the X100 class. Only 6 examples were ordered and produced of the Mk.1 variant. They were numbered X201-X206. They were built using a number of steam locomotive spare parts. They were built on the inner bogies of the AD60 Beyer-Garratt class locomotives, and used spare C36 class 4-6-0 express locomotive windows in their cabs. Their engines were rated at 260 hp (190 kW) at 2,100 rpm and had a top speed of 24 mph. The rounded shapes of the hoods and cab gave it a baby-brother appearance to the main line 42 and 44 classes then in use. The addition of a train brake allowed them to be run on the main line and also to be used as replacements for various ageing shunting locomotives. The six members of the X200 class Mk.1 variant were initially used in the Sydney metropolitan network, but did later find their ways beyond this region.
The second series of the X200 class (now distinguished as the Mk.2 variant) were different again. There were 12 examples of the Mk.2 type being numbered X207-X218. They were built on the outer bogies of the AD60 Beyer-Garratt class locomotives. Their engines were more powerful rated at 290 hp (220 kW) at 2,100 rpm and they had a higher top speed of 32 mph. This made them more practical for light line use. One was even rostered on to the Yass Tramway, previously the domain of the Z13 class 4-4-2 suburban tank locomotives. (The Z13 class were called back to Yass during winter months to provide heating in the train and they also filled in when the X200 had "failed"). The exterior design of the Mk.2 variant was more squarish, giving it the appearance of a baby-brother to the 49 class diesel locomotives introduced in 1960. Despite differences in engine horsepower ratings, both variants were rated as having a tractive effort of 17,750 lbf (79.0 kN). This was more powerful than many of the typical small and workshop steam shunting locomotives of the time.
The X200 class must be considered largely successful, as they began to replace the various ageing steam shunting locomotives in various depots of the time. They were cleaner, more efficient to run, requiring less maintenance, and also giving locomotive crews more comfortable working conditions. Another indicator of the class' success is that several examples are still operational even today, at an age of around 45 years! Unfortunately, with the volatile and ever-changing nature of rail transport companies in the modern day, it is hard to keep a 100% accurate listing of their current owners and operational areas. There is a certain amount of confusion with the numbering in this class. The numbers specified above apply to the class when first issued to traffic. In later years a certain amount of number-swapping was carried out by workshops. The biggest confusion being X101 and X212 swapping numbers, being two completely different types of locomotive! X217 and X218 later became X117 and X118, confusing the matter further. It appears that members of the X200 class were indiscriminately re-numbered into the X100 series. Many other renumberings exist. For the purposes of research it is often easier to refer to individual locomotives by their numbers when first issued to traffic and to note any number changes in brackets as below.