Gotthard Railway A 3/5 No. 931 to 938
After the first type A 3/5 express locomotives, the Gotthardbahn had Maffei develop another variant of this type in 1908. Although it was primarily intended for use on the company's valley lines, it was also intended to pull lighter trains on the mountain lines and, like its predecessors, was therefore given relatively small wheels with a diameter of 1,610 mm. Maffei used the basic construction of the Bavarian P 3/5 as a basis.
Thus, the locomotives had a bar frame and a long, narrow firebox that lay between the wheels of the second and third coupled axle. The roof of the firebox sloped backwards so that it was always sufficiently covered with water when running downhill on the 2.7 percent mountain grade. To increase efficiency, a Crawford-Clench steam dryer was used, which was replaced by the Schmidt smoke tube superheater from 1913 onwards.
The dimensions of the cylinders and parts of the valve gear corresponded to the type C 4/5 freight locomotive also supplied by Maffei in 1906 in order to reduce the number of spare parts to be kept on hand. All cylinders acted on the first coupled axle according to the Von Borries design. A piston valve was used on each side, which simultaneously controlled one high- and one low-pressure cylinder. While this arrangement was efficient, over time it resulted in damage to the valve gear.
Maffei delivered four locomotives, four more were delivered by SLM in Winterthur in the same year. On the valley lines, they could transport 350-tonne trains at one percent at 60 km/h, and at 2.7 percent on the mountain line, it was still 150 tonnes at 40 km/h. The Gotthard railway was nationalized as early as 1909, so that the locomotives were now operated by the SBB. After the Gotthard Railway was electrified, it was scrapped as early as 1925.
Technical data
General
- Built
- 1908
- Manufacturers
- Maffei, SLM
- Wheel arrangement
- 4-6-0 (Ten-wheeler)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Length
- 17.46 m
- Length loco
- 11.69 m
- Wheelbase
- 8.64 m
- Empty mass
- 70.4 t
- Service mass
- 79.8 t
- Adhesion mass
- 49.5 t
- Total mass
- 117.8 t
- Rigid wheelbase
- 3.90 m
- Axle load
- 16.5 t
- Water capacity
- 17,000 l
- Fuel capacity
- 5 t (coal)
Boiler
- Grate area
- 3.34 m²
- Firebox surface
- 15.4 m²
- Tube heating surface
- 173.2 m²
- Evaporative heating surface
- 188.6 m²
- Superheater surface
- 50.84 m²
- Total heating surface
- 239.4 m²
Power plant
- Driver diameter
- 1,610 mm
- Boiler pressure
- 15 bar
- Expansion type
- compound
- Cylinders
- four, HP: 395 x 640 mm and LP: 635 x 640 mm
Power
- Power source
- steam
- Indicated power
- 1,221 kW (1,660 PS)
- Top speed
- 90 km/h
- Starting effort
- 114.0 kN
- Starting effort simple
- 136.8 kN
Calculated values
- Factor of adhesion
- 1 : 4.26
- Optimal speed
- 66 km/h
- Power-to-weight ratio
- 15.3 kW/t
- Heating Surface Equivalent
- 367.3 m²
- Cylinder volume/HSE
- 1 : 978.92
- Adhesive weight/Total
- 1 : 1.61
- Tractive force/Heating surface
- 1 : 9.95
- Grate area/Heating surface
- 1 : 71.69
- Firebox/Tube surface
- 1 : 11.25
- Total/Superheater
- 1 : 3.71