Locomotives of the London and North Eastern Railway
The London and North Eastern Railway (LNER) produced several classes of locomotive, mostly to the designs of Nigel Gresley, characterised by a three-cylinder layout with a parallel boiler and round-topped firebox. It produced the most famous locomotive of its day, 4468 'Mallard', the holder of the world steam locomotive speed record.
Source: Wikipedia — Locomotives of the London and North Eastern Railway (CC BY-SA 4.0)