 the sr z class was an 0-8-0t 3-cylinder tank engine designed by richard maunsell and intended for heavy shunting on the southern railway, the first eight entering into service in 1929. it was a successful design and would have been built in greater numbers, but an order for a further ten was cancelled in 1930 due to the reduction in freight traffic as a result of the great depression. ==background== the newly amalgamated southern railway needed a group of powerful shunting tank locomotives to work in its marshalling yards around london and on freight transfers between them. robert urie's g16 class 4-8-0 performed this task well, and further examples were on order in 1922, but richard maunsell considered the firebox to be too large and the superheater an unnecessary expense on such locomotives. he therefore cancelled the order in favour of a new design.bradley, d.l. (1975). locomotives of the southern railway part 1. london: railway correspondence and travel society. isbn 0-901115-30-4. pp.43-7. due to the requirement for heavy shunting, the design was provided with an 0-8-0 wheel arrangement to increase traction, whilst enabling the locomotives to negotiate tight curves prevalent in goods yards. another requirement was for the locomotive to be able to maintain power after long periods of standing idle, as freight marshalling was an intermittent duty. a 1500 gallon water capacity was also required to reduce the need for regular watering. == construction history == the new class was largely designed at ashford railway works but, as a result of the unexpected need to redesign and rebuild the secr k class locomotives at ashford, maunse
0-8-0T_locomotives Railway_locomotives_introduced_in_1929 Southern_Railway_locomotives