Mechanically, the prototype Atlantean was similar to the Lowloader with an O.600 engine transversely mounted at the rear with a pneumo-cyclic gearbox situated in the rear offside corner providing drive in a straight line from the engine. The Atlantean had a light and strong fabricated frame. Light alloy floor plates were rivetted directly to the framework, fulfilling the dual purpose of reinforcing the frame and providing a foundation for the saloon floor. The platform-type sub-frame concept from the Lowloader was retained for the prototype. A drop-centre rear axle allowed the flat floor, only one step up from ground level, to continue for the full length of the bus.