Midland Great Western class A
Great Southern class D5
Ireland 1902 6 produced
The class A were the heaviest locomotives in Ireland at the time they entered service. Their job was to haul heavy express trains between the east and west coasts. Due to their high axle load, they could not be used everywhere. The first locomotive was rebuilt as early as 1916, with a superheater and larger cylinders. Due to differences, the rebuilt locomotives were designated class A1 or As. With the exception of one locomotive, all the others were only withdrawn between 1954 and 1959.
Technical data
General
| Property | as built | superheated |
|---|---|---|
| Built | 1902-1905 | 1916-1926 |
| Manufacturers | Broadstone | |
| Wheel arrangement | 4-4-0 (American) | |
| Gauge | 1,600 mm (Irish broad gauge) | |
Dimensions and weights
| Property | as built | superheated |
|---|---|---|
| Length | 16.62 m | |
| Length loco | 9.54 m | |
| Wheelbase | 6.86 m | |
| Service mass | 51.7 t | |
| Adhesion mass | 34.7 t | |
| Total mass | 88.1 t | |
| Rigid wheelbase | 2.82 m | |
| Axle load | 18.2 t | |
| Water capacity | 13,639 l | |
| Fuel capacity | 5.1 t (coal) | |
Boiler
| Property | as built | superheated |
|---|---|---|
| Grate area | 1.858 m² | |
| Firebox surface | 13.935 m² | |
| Tube heating surface | 112.691 m² | 77.342 m² |
| Evaporative heating surface | 126.627 m² | 91.277 m² |
| Total heating surface | 126.6 m² | 110.9 m² |
| Superheater surface | 19.603 m² | |
Power plant
| Property | as built | superheated |
|---|---|---|
| Driver diameter | 1,905 mm | |
| Boiler pressure | 12.4 bar | 12.1 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 457 x 660 mm | two, 483 x 660 mm |
Power
| Property | as built | superheated |
|---|---|---|
| Power source | steam | |
| Estimated power | 559 kW (760 PS) | 708 kW (963 PS) |
| Starting effort | 76.4 kN | 82.8 kN |
Calculated values
| Property | as built | superheated |
|---|---|---|
| Factor of adhesion | 1 : 4.45 | |
| Optimal speed | 45 km/h | 53 km/h |
| Power-to-weight ratio | 10.8 kW/t | |
| Heating Surface Equivalent | 196.3 m² | 200.2 m² |
| Cylinder volume/HSE | 1 : 1,104.63 | 1 : 1,207.06 |
| Adhesive weight/Total | 1 : 1.49 | |
| Tractive force/Heating surface | 1 : 12.61 | 1 : 15.60 |
| Grate area/Heating surface | 1 : 68.15 | 1 : 59.68 |
| Firebox/Tube surface | 1 : 8.09 | 1 : 5.55 |
| Total/Superheater | 1 : 4.66 |
