Super-Garratt Patent 230,888 Beyer-Garratt Locomotives in Great_Britain

Class Details by Steve Llanso of Sweat House Media

Class unknown (Locobase 15985)

Data from "Patent Super-Garratt Articulated Locomotive illustraton and comments uploaded 8 September 2018 on the Historical Railway Images thread on Flickr at [], last accessed 15 April 2023. See also Richard L Hills and D Patrick, Beyer, Peacock: Locomotive Builders to the World (Glossop, Derbyshire: Transport Publishing Company, 1982) , pp. 182-183. (Thanks to Peter Christener for his 22 October 2023 email telling us of the Beyer Peacock book and giving the page cite.)

This was a projected audruplex elargement of the basic Garratt concept.. The description notes that this unfathomably long locomotive would have generated 200,000 lb (90,719 kg or 889.64 kN) of starting tractive effort..Remarkably, B-P (possibly with Alco) envisioned a boiler, grate, and firebox big enough to handle the demands of eight live-steam cylinders. On the other hand, the illustrated locomotive on pp. 182-183 shows very small water tank and fuel bunkers.

The HRI author added "It could be called a Mallet-Garratt, as each engine section has its front half pivoted at the rear and sliding at the front in the Mallet manner." Locobase supposes, that, given the maximum axle load of 13 tons (presumably long tons of 2,240 lb), the adhesion weight would have easily exceeded 375,000 lb and total weight was estimated at 460 tons (if these are "long" tons, it converts to 1,030,400 lb or 467,382 kg).

Super-Garratt's likely width of 12 feet might not have exceeded many loading gauges, but its overall length of 142 ft (43.28 m) and maximum height of 16 ft 7 in (5.05 m) lay outside of even the biggest North American articulateds.

Atlhough he thinks it a shame that no one ever ordered one, Locobase thinks there are limits to everything. Or, as put it, "From intimate knowledge of the design of Beyer-Garratt, it is probably all for the best that the Super-Garratt never progressed beyond the drawing board."

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID15985
RailroadSuper-Garratt Patent 230,888
CountryGreat Britain
Number in Class1
Road Numbers
Number Built1
BuilderBeyer, Peacock
Valve Gear
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)25.79 / 7.86
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)29,120
Weight on Drivers (lbs / kg)
Engine Weight (lbs / kg)896,000
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)896,000
Tender Water Capacity (gals / ML)19,200 / 72.73
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)16 / 15
Minimum weight of rail (calculated) (lb/yd / kg/m)
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)26.40 / 671
Boiler Pressure (psi / kPa)176.90 / 12.20
High Pressure Cylinders (dia x stroke) (in / mm)19" x 26" / 483x660 (8)
Tractive Effort (lbs / kg)213,837 / 96994.95
Factor of Adhesion (Weight on Drivers/Tractive Effort)
Heating Ability
Tubes (number - dia) (in / mm)190 - 1.614" / 41
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 7.22 / 2.20
Firebox Area (sq ft / m2)585 / 54.35
Grate Area (sq ft / m2)160 / 14.86
Evaporative Heating Surface (sq ft / m2)7482 / 695.09
Superheating Surface (sq ft / m2)1818 / 168.90
Combined Heating Surface (sq ft / m2)9300 / 863.99
Evaporative Heating Surface/Cylinder Volume219.23
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation28,304
Same as above plus superheater percentage33,965
Same as above but substitute firebox area for grate area124,184
Power L16105
Power MT

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