Locomotives Nos. 6 & 7

Design

Coal fired steam locomotive.
The requirements for this generation of locomotives stipulated the ability to convey two instead of the usual single passenger coach. The prototype was taken from the 1929 Type S1 locos of the Savoy Bahn Aix-les-Bains - Mont Revard.

Construction

Cast steel parts as per type S1

Motion

Transmission via front mounted cranks and gear reduction.
Note: the ride characteristics were improved by the positioning the cylinders inside near to the centre of balance.

Wheel arrangement

4-0-2

Note: adhesive power is only transmitted via the pinions

Pinion diameter

573 mm with 15 teeth

Rail wheel diameter

653 mm
Note: these wheels share a common axle with the pinions but they are not rotationally coupled to these.

Trailing rail wheels

520 mm

Gear reduction

1 : 2.2

Length

6410 mm over buffers

Bunker capacity

550 kg (roof mounted)

Fuel consumption

350 kg per return journey to Rothorn Kulm

Boiler capacity

1050 l

Water tank capacity

1500 l

Water consumption

2000 l per return journey to Rothorn Kulm

Power output

220 kW / 300 HP

Power output

50 kN

Speed

9.0 km/h maximum at 250 ‰ (1 in 4 gradient) and under full loading

Drawbar power

12,800 kg (Estimated) (buffer thrust)

Boiler pressure

14 bar (205 psi)

Superheaters

Schmidt design. Operating at 380°C

Cylinder diameter

Piston stroke

400 mm

Heating surface area firebox

4 m²

Heating surface area tubes

26 m²

Heating surface superheaters

6.45 m²

Heating surface area total

36.45 m²

Grate area

0.78 m² Note: there is no firing during the return journey, this results in better average values for emissions. During the return journey the cylinders are used as air compressors, thereby braking the train, this process generates considerable heat which is removed by means of water injection into the cylinders, the resulting steam is exhausted via a pipe at the rear of the cab roof.

Braking

Riggenbach System

Handbrake

Fitted to driver and fireman’s positions

Service weight

20'000 kg weighed at 18’830 kg date unknown

Dry weight

16'700 kg weighed at 15’465 kg date unknown

Purchase cost

51’000.00 CHF (1933), includes turbo generator for lighting. 67’000.00 (1936).

Overhauls

Major overhauls at the DB works in Offenburg during 1971/72 included new fireboxes. Frame cracks and breaks during several decades made these locos problematic to maintain

Firing

In 1990 modified from briquette to coal firing

Crew

1 driver, 1 fireman

H 2/3 6

SLM* 3567

1933: Commenced service with BRB

H 2/3 7

SLM 3611

1936: Commenced service with BRB, 2011 currently not in service restart planned

*SLM: Swiss Locomotive- and Machine Works, Winterthur (1871-1998)