South Australian class Y
The most numerous class of steam locomotives on the South Australian Railways was the 2-6-0 class Y built between 1885 and 1898 for their Cape gauge network. Noticeable features were the low running boards which were sloped upwards at the front to provide space for the inclined cylinders and a dome that had the same height as the chimney. They were intended for freight service, but sometimes also used for passenger trains.
50 were built by Beyer, Peacock & Co. in England, 77 by James Martin & Co. in Australia and two more by the Railway's own Islington workshops. More locomotives of nearly identical design were built as Silverton Tramway class Y, Tasmanian Government Railways class C and Western Australian Government Railways class G. Between 1904 and 1924, 58 were rebuilt to class Yx. These got a new boiler with Belpaire firebox and a pressure of 185 instead of 150 psi.
Later some where used on the timber lines of Western Australia, while others were sold to railway construction companies. In 1941 and 1942, 18 were sold to the Commonwealth Railways to become class Nfb. In 1948, seven of these were sold again to the Tasmanian Government Railways and became class F. Today ten are preserved, with Yx141 being operational.
Technical data
General
| Property | as built | rebuilt Yx |
|---|---|---|
| Built | 1885-1898 | 1904-1924 |
| Manufacturers | Beyer, Peacock & Co., Islington, James Martin & Co | |
| Wheel arrangement | 2-6-0 (Mogul) | |
| Gauge | 1,067 mm (Cape gauge) | |
Dimensions and weights
| Property | as built | rebuilt Yx |
|---|---|---|
| Length | 11.96 m | |
| Wheelbase | 4.06 m | |
| Total wheelbase | 11.02 m | |
| Service mass | 26.4 t | 28.7 t |
| Adhesion mass | 22.7 t | 23.7 t |
| Total mass | 48.5 t | 50.8 t |
| Rigid wheelbase | 2.29 m | |
| Axle load | 7.6 t | 8.1 t |
| Water capacity | 7,276 l | |
| Fuel capacity | 4.6 t (coal) | |
Boiler
| Property | as built | rebuilt Yx |
|---|---|---|
| Grate area | 1.27 m² | 1.238 m² |
| Firebox surface | 6.457 m² | 7.079 m² |
| Tube heating surface | 65.915 m² | 67.801 m² |
| Evaporative heating surface | 72.372 m² | 74.88 m² |
| Total heating surface | 72.4 m² | 74.9 m² |
Power plant
| Property | as built | rebuilt Yx |
|---|---|---|
| Driver diameter | 991 mm | |
| Boiler pressure | 10.3 bar | 12.8 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 368 x 508 mm | |
Power
| Property | as built | rebuilt Yx |
|---|---|---|
| Power source | steam | |
| Estimated power | 186 kW (253 PS) | 261 kW (355 PS) |
| Starting effort | 61.1 kN | 75.4 kN |
Calculated values
| Property | as built | rebuilt Yx |
|---|---|---|
| Factor of adhesion | 1 : 3.64 | 1 : 3.09 |
| Optimal speed | 19 km/h | 21 km/h |
| Power-to-weight ratio | 7.0 kW/t | 9.1 kW/t |
| Heating Surface Equivalent | 104.7 m² | 110.3 m² |
| Cylinder volume/HSE | 1 : 1,034.23 | 1 : 981.54 |
| Adhesive weight/Total | 1 : 1.16 | 1 : 1.21 |
| Tractive force/Heating surface | 1 : 17.65 | 1 : 21.04 |
| Grate area/Heating surface | 1 : 56.99 | 1 : 60.48 |
| Firebox/Tube surface | 1 : 10.21 | 1 : 9.58 |