[PRCo] Re: Pgh Railways Street Car Operators Wanted Ad

[TEP]

No typo. The carbon shoes on a trolleybus require slightly more than twice
the upward spring force of a streetcar trolley pole, nominally 72 lb each.
They have to stay on even when off-centre -- the maximum roam is 14 ft.

The operator is instructed to only handle one pole at a time but this is
often breeched meaning grabbing both ropes at once -- and the 140 lb uplift
requires at least that body weight according to my physics. 

At  the time of the ad the US was contributing to the UK war effort through
lend-lease, but was not at war, and there were strong forces in the USA
opposing entry, despite Roosevelt's views. So I might be speaking German now
if not for Pearl Harbor!

Tom P.
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Phillip Clark Campbell wrote: 2: Is that a typo - 70#? Ohio Brass recommends
a maximum of 30-32 pounds for wheels; 25-30 pounds for shoes at wire height
of 18-feet. I understand Prc used a modestly higher figure for interurbans.
In 1941 which we are discussing, OB was the standard to follow. Modern
trolley poles today may use less 'tension' as mass of pole is lighter. 70#
isalmost triple the low figure for shoes; poles would snap in two under such
tension while severe damage would result to the overhead on dewirements
regardless of effectiveness of retrievers.