Only single deck vehicles were used in service, as there were a number of low bridges, and the service to Manvers initially stopped short of the Manvers Main colliery, until the road under the railway bridge could be lowered sufficiently. The four vehicles saw little use, as they were withdrawn in 1922, after the arrival of two vehicles made by Associated Equipment Company (AEC) and another of the same make in 1924. This was another pioneering move for the manufacturer, as AEC were the first company with experience at manufacturing petrol chassis rather than tramway equipment to supply trolleybuses. Their first model was the 602, which was deliberately kept simple to aid maintenance, and had a single motor made by British Thomson-Houston and rheostatic control. Six were manufactured, with three going to Mexborough. Richard Garrett & Sons were a brief player in trolleybus manufacturing, starting in 1925 and folding in 1931. Following their appearance at the Commercial Motor Show in November 1927, they had received an order from Doncaster Corporation for four 3-axle 60-seat vehicles. The first one to be completed was tested on the Mexborough system in March 1928, although it was unregistered at the time, and ran using trade plates. As the system expanded in the late 1920s, 30 Garrett type O vehicles were purchased between 1928 and 1930. Electrical equipment was by British Thomson-Houston with bodywork by Garrett. They had a centre entrance for the passengers, and like all subsequent vehicles, 32 seats. The six English Electric vehicles purchased second-hand from Notts and Derby in 1937 departed from the standard layout by having front entrances. Six more second-hand vehicles came from Hastings in 1943, and although they were given fleet numbers from 70 to 75, only Nos. 71, 74 and 75 were actually used in public service, and then only until the end of the Second World War. They were the only 3-axle vehicles that the Company ran, all the rest having 2 axles.