Chassis: Leyland Motors PDR1/1
Leyland used a reasonably simple system to identify chassis types. PDR1/1 tells us the following:
 | The P tells us that it is a Passenger vehicle |
| The D tells us that the chassis has been designed to mount a Double deck body (although some later Atlantean chassis were fitted with single deck bodies - Portsmouth were the largest user of this type) |
| R shows that the engine is at the Rear of the chassis |
| and 1/1 indicates that it is the first type and sub-type of that class of vehicle |
any other blurb on the chassis?
Engine: Leyland O.600
A powerful and long established diesel engine, mounted crossways at the rear of the chassis.
Specification:
| Capacity | 600 cubic inches (hence O.600), approximately 9.8 litres |
| Maximum Power | 130 bhp @ 1800 rpm |
| Layout | 6 cylinder, in-line |
| Fuel | Diesel |
Transmission
4-speed semi-automatic Leyland electro-pneumatic epicyclic. Gear changing in city traffic was very tiring for the driver of a conventional bus and so various means had been tried to make the job of driving easier. In London, the AEC Regent 3 RT class had pioneered pre-select gear changes. In this system, the driver selects the next gear to be required in advance of actually needing it and in due course presses a pedal - in the same position as the normal clutch pedal - that actually causes the gears to change.
With the Leyland system, the driver has a short lever mounted close to the steering wheel (picture required) that is used in the same manner as a conventional manual change. A fluid flywheel, or torque converter replaces the conventional clutch. The driver's gear lever works a series of electrical contacts that in turn operate air valves that control the brake bands and effect the gear changes. There is no clutch pedal, the gear change takes no effort and if well executed is very smooth, increasing the comfort for the passenger.
Drive from the gearbox output to the back axle is through an "angle shaft". This design has worked well on the Leyland chassis. Other rear-engine buses have used different arrangements to transmit the drive, not always successfully.
Brakes
Air operated service brake, mechanical hand brake working on rear wheels.
