The small engine policy remained in place into the 1920s and remained an influence during the early years of the Midland's successor the London, Midland and Scottish Railway, its Chief Mechanical Engineer for most of the 1920s being Henry Fowler, a long-standing Midland engineer and former CME of that company. Midland-era standard designs were continued or lightly updated and constructed for use across the new LMS network. Many of these types proved ill-suited or inadequate for routes and operating practices away from ex-Midland territory - while ex-Midland locomotives were imposed on the new LMS, the operational practices that went with them were not, on top of still-rising demands with regard to train speeds and weights. This left Midland-designed 'small engines' being worked to the full on heavy trains by crews used to working their engines as hard as possible. Under these conditions many of the designs proved inadequate in terms of both performance and reliability (such as the frequent axle bearing failures afflicting many ex-Midland LMS engines in the 1920s) and this left the LMS with a shortage of modern motive power by the late 1920s. Fowler designed the Royal Scot class locomotives in 1927, which effectively ended the Midland small engine tradition and he was replaced by William Stanier in 1932 who brought in a new generation of modern 'large engine' designs, greatly influenced by his previous employer, the Great Western Railway.