The most obvious difference is that the driving wheel diameter was reduced from 7 ft 0 in (2.134 m) on the Midland locomotive to 6 ft 9 in (2.057 m) on the LMS version. They were given the power classification 4P.

The London, Midland and Scottish Railway (LMS) Fowler 2-6-4T was a class of steam locomotive passenger tank engine designed by Henry Fowler. 42421 at Hibel Road station in 1959 - this is one of the Fowler 4MTs with later style side window cabs. 125 examples of the class were built.

Sir William Stanier's London, Midland and Scottish Railway (LMS) Class 4P 2-Cylinder 2-6-4T was a class of 206 steam locomotive built between 1935 and 1943. They were based on his LMS 3-Cylinder 2-6-4T.

The LMS 4P Class was a series of 2-6-4T steam locomotives that were built for the London, Midland and Scottish Railway by Derby Works. Most of the class were used on longer-distance commuter trains from stations in London, Manchester and other large towns.

In the early years of the LMS, the 4P 4-4-0’s were the main express locomotive type available on some major routes. With Stanier’s arrival, they were quickly replaced by Jubilee’s and then acted as support locomotives or were sent off to other parts of the network to replace older locomotives on secondary routes.

The Stanier 4P 2-6-4T’s were the third evolution in the standard LMS large passenger tank family. They were a simplified version of the 3 cylinder tanks as it was found the central cylinder was an unnecessary expense.

The LMS Fowler class 4P was the first in a series of 2-6-4T tank locomotives designed for long-distance commuter services. It was introduced in 1927 by Henry Fowler and formed the basis for derivatives by Stanier, Fairburn and Riddles. 125 of this class were build in Derby until 1934.

The London, Midland and Scottish Railway Compound 4-4-0 was a class of steam locomotive designed for passenger work. 195 engines were built by the LMS, adding to the 45 Midland Railway 1000 Class, to which they were almost identical. They were given the …

They were excellent and popular engines and became the first in a long line of 2-6-4T locomotives to be built. The 42300 class had parallel boilers whilst all of the later designs had taper boilers. They also had straight tops to the tanks.

Horwich Works turned out 1115-11130 in 1925 and 1131-1134 in 1926. North British Locomotive Company delivered its only 4Ps as works numbers 23229-23253 in 1925. Vulcan Foundry supplied works numbers 3833-3857 in 1925. Its other batch came in 1927 with works numbers 3990-4047. (Road numbers ran 1185-1199, 900-909, 925-934, and 910-924.)