Brienz Rothorn Bahn 0-4-2 Locomotives in Switzerland


Class Details by Steve Llanso of Sweat House Media

Class 12 (Locobase 5300)

Among the very few new-built locomotives delivered in the 1990s were 8 constructed by SLM for tourist rack railroads in Switzerland. The design incorporated Porta's principles for better firebox combustion. Also, the boiler is so well insulated that it maintains a head of steam overnight and can reach full pressure in 10-15 minutes. Like many rack engines, the boiler is tilted on its frame so that the boiler stays level as the running gear climbs steep slopes.

Compared to SLMs 1933 rack engines, says the Ultimate Steam Page's page on this locomotive ([link]), weight in service is cut by 25% while power is up 36% (a power-to-weight ratio increase of 82%) and average trip speed up by 56%. Fuel consumption is lower by 41%. SLM claims a thermal efficiency of over 10%. On the 2.5% grade, the engine has a 17 metric ton load capacity. On the 2.2% grade it's 22.6 tonnes, and climbing 2% can take 23.5 metric tons.

Brienz-Rothorn-Bahn (BRB) bought 2, Osterreichen Bundesbahnen (OBB) 3, Montreux-Glion-Rochers-de-Naye-Bahn (MGN).

Additional data from a report given to a 1998 Conference in Barcelona Modern Steam Traction and the Protection of the Environment by Reinhard Serchinger.

NB: Tube length is an estimate based on the calculation of tube surface area by subtracting reported firebox heating surface from reported total evaporative heating surface


Class H 2/3 (Locobase 5987)

By now relegated to comparisons with the 1990s trio built by SLM (as DLM) -- see Locobase 5300 -- these were the first rack locomotives on this short, challenging line. The BRB has an average incline of 22.5% over the 7.6-km (4.66-mile) route; the elevation changes 1,670 m (5,090 ft). Six tunnels pierce the mountains along the way for a total length of 690 m (2,264 ft or 9% of the distance) and the tightest curves have radii of 60 m (197 ft).The line opened in 1892 using these locomotives.


Class H 2/3 - 1933 (Locobase 5988)

Data from "2nd generation steam locomotives - built 1933/36

H2/3 6&7" on the BRB websited at [link], last accessed 16 December 2021.

These second-generation rack locomotives remain in service on the BRB. The website's account notes that the return trip from Brienz to Rothorn will consume 350 kilos kg (0.38 short tons) of coal and 2,000 litres (528 US gallons) of water. The crew of three includes "A driver, a stoker and a conductor" who serve up to 80 people.

Principal Dimensions by Steve Llanso of Middle Run Media
Class12H 2/3H 2/3 - 1933
Locobase ID5300 5987 5988
RailroadBrienz Rothorn Bahn (BRB)Brienz Rothorn Bahn (BRB)Brienz Rothorn Bahn (BRB)
CountrySwitzerlandSwitzerlandSwitzerland
Whyte0-4-2RT0-4-2RT0-4-2RT
Number in Class852
Road Numbers12, 14, 151- 56-7
Gauge80 cmStdStd
Number Built852
BuilderSLMSLMSLM
Year199418911933
Valve GearHeusingerHeusingerHeusinger
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.79 / 2.07 4.42 / 1.35
Engine Wheelbase (ft / m)11.98 / 3.65 9.84 / 3
Ratio of driving wheelbase to overall engine wheelbase 0.57 0.45
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)24,251 / 11,00026,455 / 12,00028,660 / 13,000
Engine Weight (lbs / kg)35,274 / 16,00037,479 / 17,00041,888 / 19,000
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)370 / 1.40317 / 1.20396 / 1.50
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)317 / 1200 0.90 / 1 0.60 / 0.55
Minimum weight of rail (calculated) (lb/yd / kg/m)
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)25.70 / 65322.60 / 57422.60 / 574
Boiler Pressure (psi / kPa)232.10 / 1600203.10 / 1400203.10 / 1400
High Pressure Cylinders (dia x stroke) (in / mm)11.02" x 15.75" / 280x40011.81" x 21.65" / 300x55011.81" x 15.75" / 300x400
Tractive Effort (lbs / kg)14,683 / 6660.1023,066 / 10462.5716,780 / 7611.29
Factor of Adhesion (Weight on Drivers/Tractive Effort) 1.65 1.15 1.71
Heating Ability
Tubes (number - dia) (in / mm)38 - 1.5" / 38
Flues (number - dia) (in / mm)15 - 4.5" / 114
Flue/Tube length (ft / m) 8.25 / 2.51
Firebox Area (sq ft / m2)55.31 / 5.1437.66 / 3.5043.06 / 4
Grate Area (sq ft / m2) 9.68 / 0.90 7.10 / 0.66 8.40 / 0.78
Evaporative Heating Surface (sq ft / m2)321 / 29.83393 / 36.52323 / 30.02
Superheating Surface (sq ft / m2)142 / 13.2075 / 6.9769 / 6.41
Combined Heating Surface (sq ft / m2)463 / 43.03468 / 43.49392 / 36.43
Evaporative Heating Surface/Cylinder Volume184.62143.17161.75
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation224714421706
Same as above plus superheater percentage294316732013
Same as above but substitute firebox area for grate area16,817887310,320
Power L110,72435014441
Power MT

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