[PRCo] Re: Pittsburgh Overhead

[Dietrich, Robert J.]

The rumor I heard was that the overhead was designed to withstand a
tornado.  True or not it did the job - the tornado went up the hill to
avoid a conflict with that mass of steel.



-----Original Message-----
From: pittsburgh-railways-bounce at lists.dementia.org
[mailto:pittsburgh-railways-bounce at lists.dementia.org] On Behalf Of Bob
Rathke
Sent: Wednesday, March 16, 2005 7:47 PM
To: pittsburgh-railways at dementia.org
Subject: [PRCo] Re: Pittsburgh Overhead

I think that John is on to something here.  A parallel in the commercial
aviation industry: in the 1950's, the approach lights to airport runways
were attached to heavy steel towers (not unlike high voltage electrical
power transmission towers).  Numerous  accidents occurred when too-low
aircraft struck the towers - the towers survived the impact, but the
aircraft crashed to the ground.

The old structures were called "battleship towers", and by the 1980's
most
were replaced by the lighter, frangible (bendable) towers that are in
use
today.

I always called PAT's catenary support structures "battleship towers."

Bob 3/16/05

----------------------------

> Pittsburgh was an early light rail project.  The available consulting
> engineers were probably (guess on my part) more familiar with metros
then
> light rail.
>
> John