The “Standard” SOS class of single-deck bus operated by Birmingham and Midland Motor Omnibus Company Limited (BMMO—Midland “Red” Motor Services) dated from 1923 to 1925, and when new they had been considered a modern, forward-thinking design. However, this was a period of rapid innovation and progress, especially in the area of vehicle styling, and by the late 1920s the class was already looking outdated. Mechanically the vehicles still had about five years of life remaining, but the tall, upright and angular bodywork design was quickly becoming obsolete.
In 1929, in an effort to find ways to modernise the fleet without the expense of designing and building a completely new class of vehicle, BMMO experimented in further extending the life of one of their “Standard” SOS vehicles by overhauling the chassis and replacing the dated body with new bodywork built to a new, modern design. The experiment was successful and following the prototype, a production batch consisting of fifty vehicles were converted in 1930. The company also carried out the same conversion for other operators of the “Standard” SOS type.
These converted buses were classified as SOS “ODD”, although the exact meaning of this is unknown.
The “Standard” SOS chosen to become the SOS “ODD” prototype was registration number HA2392, which had been the first vehicle chassis to be fully built by BMMO (chassis number BMO.1) at their Bearwood depot workshops in 1925.
For the conversion, HA2392 was withdrawn from service in 1929 and the original home-built “Carlyle” bodywork removed. The chassis was then extensively refurbished, receiving new running units and smaller wheels to help lower the vehicle and reduce entrance step height. The refurbished chassis was fitted with new B27F bus bodywork by United Automobile Services of Lowestoft (later known as Eastern Coach Works), and returned to BMMO in late 1929.
The conversion gave the vehicle a much more modern and attractive look, and after evaluation was judged to be a success, resulting in a production batch being ordered. The prototype was delivered in an experimental new livery, with a white upper body and thick dark band below the windows, but this new livery was not so successful and was never used on any other vehicle.
Following the success of the prototype, a batch of fifty production conversions were ordered for 1930. Only examples of the BMMO built “1925 Standard” were chosen for the conversion with examples of the earlier “1924 Standard” built by Tilling-Stevens being overlooked, probably due to either the numerous minor specification differences on the earlier vehicles or the slightly shorter wheelbase.
The production conversions differed slightly from the 1929 prototype in that they had one less seat, with B26F layout, and a slightly different window design. Some examples had the new bodywork fitted by United Automobile Services at their factory in Lowestoft, while the remainder had bodywork supplied in kit form by United Automobile, which was then fitted and finished in-house by BMMO. Unlike the prototype, all of these vehicles were new in the more conventional livery of overall red with silver roof and gold outlining.
By the time of the SOS “ODD” conversions in 1930, all of BMMO production single-deck buses were being built to forward control design and had 34-seat layouts, so with only 26 seats these vehicles not considered suitable for busy urban services. They were therefore used on quieter routes, often in rural areas, but they were well suited to this task and provided many years of reliable service. The layout was also well suited for early one-man operation experiments, but this was not introduced on regular services until the mid-1950s, over 15-years after the last examples had been withdrawn. By the time they were withdrawn, all examples had their capacity increased to 30 by adding an extra row of seats.
The SOS “ODD” conversion extended the life of the original “Standard” SOS chassis by around four years with the vast majority being withdrawn in 1938, compared to vehicles in original condition which had all gone by the end of 1934.
Three examples saw further use as driver training vehicles until 1943 (registration numbers HA2443 and HA2450) and 1946 (registration number HA2442), while one example (registration number HA2453) survived as a tree cutter until 1952.
Details of these early vehicles are not easy to come by, so all of the information on this page has been sourced using various previously published works by John Seale, Paul Gray and Malcolm Keeley, and the Birmingham and Midland Motor Omnibus Trust (BaMMOT).