The first 19 locomotives that Brunel had procured in 1838 were partly adventurous designs to reach high speeds. On the one hand there were the “Snake” and “Viper” locomotives from the Haigh foundry, which were brought to higher speeds with a gearbox with a ratio of 2:3 and had the wheel arrangement 2-2-2. Less conventional were the two Hawthorn locomotives developed by Thomas Elliot Harrison, which used two cars to split the boiler and engine.
The first of these was the “Thunderer”, where the boiler and driver's stand were on a three-axle chassis. The cylinders were housed on another, two-axle chassis together with a gearbox with a ratio of 10:27. Here both axles with six feet wheels were driven. The live steam was routed to the engine chassis and the exhaust steam back to the smoke box via elastic pipes.
The “Hurricane” got rid of the gearbox by increasing the size of the driven wheels to exactly ten feet. For reasons of space, only one axle was driven, which is why two carrying axles were added and the engine unit was thus given the wheel arrangement 2-2-2. Both “Thunderer” and “Hurricane” were only used until December 1839 and their boilers were then used as stationary steam generators and for a freight locomotive. Thanks to the experience with the locomotives, gearboxes and equally divided locomotives were dispensed with in the future and high speeds were achieved in other ways.
