After Grouping the LMS continued the Midland Railway's "small engine policy" of hauling trains using two or three locomotives of moderate power coupled together. This led to most of the Toton (Nottinghamshire)-Brent (London) coal trains being double-headed by 0-6-0 locomotives. It was realised that double heading was uneconomical so a Garratt locomotive was ordered from Beyer, Peacock and Company. However the LMS Derby design office insisted on the fitting of their standard axleboxes to the design. These axleboxes were barely adequate for the LMS Class 4F 0-6-0 locomotives, on which they frequently overheated, and were a major weakness on the LMS Garratts. They were also always heavy on coal and maintenance.