They were very very reliable because erm, the motive power was in a motor, electric motor, not a lot of parts to go wrong but er once you started the motor buses they had to send people away to  to be taught the mechanics of motor buses, so you had the old die-hards of the fetters, trolley buses, who never did take to motor buses and course the younger ones came into their own then, who were able to adapt to the modern motor bus.