Re: Progressive Tram Design in the 30s (was: Citadis: Seat Layout)

["David Bennetts" <davibenn@ozemail.com.au>]

>
> The "average" Australian tram design of the 1930s was a two truck
> "drop centre" car with manual doors (if any), which absolutely
> required a conductor to be safely operated, running on what was
> basically early 1900s "K controller" technology.... the lower numbered
> class variants of the Melbourne "W" series cars are well known
> examples of this level of technology.
>
> From a technology point of view, this was in fact step back from some
> of the earlier designs (particularly the Sydney P and Adelaide H
> cars), and it took the best part of 40 years for Australian tramcar
> design to again rise above that level.
>
> Cheers,
>
> Bill

The Sydney P Car was considered advanced because it had a body which could
be closed against the weather but with manually operated canvas doors,
automatic remote acceleration equipment, and Tomlinson autocouplers with air
piping and electrical connections incorporated within the coupler itself.
The Adelaide H Cars shared the autocouplers and automatic acceleration
equipment, but had enclosed bodies and of course folding doors which were
controlled by the driver, a much safer arrangement for passengers and crew
(particularly the conductors who had to walk the footboards on the P cars in
all weathers.

There were a lot of other features of the P class design which left a lot to
be desired. The brakes were manual lapping, which meant it more difficult to
control than self lapping brakes applied to the R series onward.  If the
brake pressure fell below about 40 psi, controllers would not operate, so
you could lose both air brake pressure and emergency braking, relying
totally on rather ineffective handbrakes.  If you tried to stop a coupled
set in this condition going down hill it would be almost impossible.

Although the R and R1 class trams were simpler electrically and weren't
designed to run in coupled sets, they were also easier to maintain and were
much more comfortable for passengers and crew in normal service conditions.

Regards

David Bennetts