North-East Railway A 2/4
Swiss Federal Railways A 2/4
Switzerland 1898 50 produced
Starting in 1898, the Swiss North Eastern Railway got 25 4-4-0 express locomotives from the SLM. They were called A 2/4 and were two-cylinder compounds. Being the only inside-cylinder locomotives of the NOB, their designers hoped to get smoother running characteristics. The Walschaerts valve gear was located on the outside.
On flat lines, they were usually used in trains of 300 to 600 tonnes and 200 to 240 tonnes on 1.2 percent. After the NOB became part of the SBB in 1902, the SBB ordered 25 more. The newer locomotives had a steam and a sand dome, while the earlier ones didn't have any domes. Only the three oldest were retired in 1917, all others followed in 1925.
Technical data
General
| Property | 1898 variant | 1903 variant |
|---|---|---|
| Built | 1898-1096 | |
| Manufacturers | SLM | |
| Wheel arrangement | 4-4-0 (American) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | 1898 variant | 1903 variant |
|---|---|---|
| Length | 15.82 m | |
| Wheelbase | 7.20 m | |
| Empty mass | 27.3 t | 29.2 t |
| Adhesion mass | 31.7 t | 33.8 t |
| Total mass | 81.3 t | 84.5 t |
| Rigid wheelbase | 2.60 m | |
| Water capacity | 12,000 l | 13,800 l |
| Fuel capacity | 6 t (coal) | |
Boiler
| Property | 1898 variant | 1903 variant |
|---|---|---|
| Grate area | 2.2 m² | |
| Firebox surface | 10.5 m² | |
| Tube heating surface | 128.6 m² | |
| Evaporative heating surface | 139.1 m² | |
| Total heating surface | 139.1 m² | |
Power plant
| Property | 1898 variant | 1903 variant |
|---|---|---|
| Driver diameter | 1,830 mm | |
| Boiler pressure | 13 bar | |
| Expansion type | compound | |
| Cylinders | two, HP: 460 x 660 mm and LP: 680 x 660 mm | |
Power
| Property | 1898 variant | 1903 variant |
|---|---|---|
| Power source | steam | |
| Estimated power | 550 kW (748 PS) | |
| Starting effort | 57.9 kN | |
| Starting effort simple | 69.4 kN | |
Calculated values
| Property | 1898 variant | 1903 variant |
|---|---|---|
| Factor of adhesion | 1 : 5.38 | 1 : 5.73 |
| Optimal speed | 58 km/h | |
| Power-to-weight ratio | 6.8 kW/t | 6.5 kW/t |
| Heating Surface Equivalent | 191.6 m² | |
| Cylinder volume/HSE | 1 : 1,197.97 | |
| Tractive force/Heating surface | 1 : 8.69 | |
| Grate area/Heating surface | 1 : 63.23 | |
| Firebox/Tube surface | 1 : 12.25 | |
