This strange machine was a collaboration between Fell Developments Ltd and the LMS, which aimed to address several of the perceived weaknesses of diesel powered rail traction. Weight was reduced by using several small engines, meaning that both the engines and their supporting structure could be lighter. This was also expected to save time in maintenance as an individual diesel engine could be exchanged more easily and with lighter equipment.No.10100 had four main engines and used differential gearing to transmit the power. It was originally built as a 4-8-4 with the coupling rods connecting the centre four pairs of driving wheels, but was later modified to 4-4+4-4.It was completed in late 1950 and made its first trial run on 9th January 1951, possibly as depicted in this picture taken at Stoke Junction as a group of interested railwayman watch the locomotive pass by.