After 1940, the vehicles were identified by the company's initials, BMMO, and supplied solely for the BMMO company's own use. Codes later used for buses were FEDD (Front Entrance Double Decker), REDD (Rear Entrance Double Decker), Coaches were initially classified "ONC", but later used a prefix of "C" – or "CM" for Motorway coaches. Single Decker models after the war were numbered S6, then S8 through S23, Double Decker models D1 through D10. The D10 was, in some opinions, the pinnacle of BMMO bus design – a double decker with front entrance/rear exit and an underfloor engine, but only two were produced. AD2, GD6 and LD8 were exceptions to the normal designation system – these codes referred to batches of respectively AEC, Guy and Leyland vehicles acquired when the manufacturing operation could not meet the heavy demand. Individual buses were numbered from (around) 2000 to 5900 – registrations (usually) incorporated the last three numbers of the serial, and a letter prefix of three letters ending in "HA" ( a Smethwick origin registration mark). This relationship did not apply to the limited number of buses gained as a result of acquisition of other operators. Bus manufacture, overhaul and accident repair was carried out at Carlyle Works, adjacent to the Rotton Park Reservoir in Edgbaston, Birmingham. Nearby to the works was BMMO's head office, in Vernon Road, Edgbaston. Historical list of Midland Red garages Other short time-span garages (either owned or rented) included: Birmingham, Ladywood Road (Five Ways Inn yard); Coventry, Sandy Lane; Cradley, (GWR station yard); Halesowen, Mucklow Hill (GWR station yard); Hereford, Bridge Street (Black Lion Yard); Kingswinford, The Portway; Leicester, Frog Island; Leicester, Hastings Road; Leicester, Welford Road; Nuneaton, Burgage Walk (ex NWMO&T Co); Nuneaton, Heath End Road; Nuneaton, the former Empire theatre; Sedgley, WDET Co depot; Shrewsbury, Abbey foregate (ex Allen Omnibus Co); Shrewsbury, Roushill; Stafford, Co-operative Street; Wellington, Mansell Street. Timeline 1904: Formation of BMMO. 1905: First services. 1914–1920: Rapid spread of services outside Birmingham to 'Paint the Midlands Red'. 1920s: Development of long-distance coach routes using charabancs. 1923: First production run of BMMO buses, SOS 'S' type – one of the first British buses to have pneumatic tyres. 1927: 'QL' type bus produced, the first Midland Red bus design to have brakes on all wheels. 1930s: Development of petrol and diesel engines. Experimental rear-engined buses built. 1940s: Experiments with, and production of under-floor engined single-deck buses.