Stories From Sodor Wikia
Main Page
Behind the Scenes

Bertha is a strong tender engine who works as the banker at Gordon's Hill.


Stories From Sodor:Future

Season 22


Bertha is the epitome of the phrase "gentle giant". She's quite timid upon meeting someone for the first time, but becomes more outgoing the more comfortable she becomes.


Bertha is based on the Midland Railway's 0-10-0 tender engine built specifically for banking duties on the Lickey Incline in Worcestershire. The engine, known as "Big Bertha" or "Big Emma" by railwaymen and railway enthusiasts, was built at the Midland Railway's Derby Works in 1919.

Big Bertha's cylinder arrangement was unusual. There were four cylinders but only two sets of piston valves because there was insufficient space under the smokebox to fit piston valves for the inside cylinders. Instead, the large outside piston valves (as well as supplying the outside cylinders) supplied the inside cylinders through cross-over steam ports. The steam-flow characteristics would have been poor (because of the length of the ports) but this would not have mattered unduly in an engine that ran only at slow speed. It has been suggested that this design has been influenced by the four-cylinder cross-ported arrangement of the Italian 0-10-0 FS Class 470 heavy freight locomotive (in which this was motivated by its being part of an asymmetrical compound design), of which a complete set of drawings were stored at Derby.

With a weight of 105 long tons (107 t) and 10 driving wheels with a diameter of 4 ft 7+1⁄2 in (1.410 m), she had a tractive effort of 43,300 lbf (193 kN). She, the LMS Garratts, and, later, LNER's class U1 Garratt were the only locomotives not given a power classification by either the LMS or BR, either because the bankers were designed specifically for the job of providing extra power at slow speeds and were not suitable for normal train working, or because their starting tractive effort fell well outside the system and it was not worth extending it for so few machines.

She was withdrawn on 19 May 1956 and scrapped by Derby Works in September 1957, having covered 838,856 miles (1,350,008 km) mostly on the Lickey. BR standard class 9F number 92079 took over, acquiring Big Bertha's electric headlight for the duty.


Bertha is painted grey with black lining and wheels.


Brendam Branch Line