[PRCo] Route 56

Mon May 5 15:28:13 EDT 2014

The original mapping was at 15 minutes, except in the wilderness, where it
was 30 minutes.  The 7.5 series originated about the time of the second war.

You can find all of the historic USGS maps on their website and download
them.

-----Original Message-----
From: pittsburgh-railways-bounces at mailman.dementix.org
[mailto:pittsburgh-railways-bounces at mailman.dementix.org] On Behalf Of Fred
Schneider
Sent: Monday, May 05, 2014 3:11 PM
To: Western PA Trolley discussion
Subject: Re: [PRCo] Route 56

I was hoping I could find an old 15 minute USGS quad on line that would show
the old carline in Dravosburg but the oldest map on the USGS website was a
1953 7.5 minute map.   At least you can match it with the Pen Pilot photo to
see the horseshoe curve.  

The curve is just to the left of the letter D in the word Dravosburg with
the highway wrapping around it.   

I do not mean to speak down to you or insult any of you but there may me one
or two who might appreciate the education.   The term 15 minute or 7.5
minute refers to the amount of the earth that the map covers.   Each degree
of latitude and longitude can be divided into 60 minutes and each minute
into 60 seconds.   So a 15 minute map covers an area 25% of a degree of
latitude and longitude.  A 7.5 minute map covers 12.5% of a degree.    It
would take 16 of the 15 minute maps to cover an area 1 degree x 1 degree but
64 7.5 minute maps to cover the same area.   

All of the USGS (US Geological Survey) mapping was originally done in 7.5
minutes.  Sometime around 1950 they switched to the much larger scale.
Then sometime around the 1990s, the Government Printing Office even offered
to buy back all the obsolete old maps from stores that still had them so you
cannot even find the old maps any longer.   

Next lesson.   This map has a contour interval of 20 feet, meaning the brown
lines are drawn for every 20 feet of elevation above sea level and every
even one, i.e. every fifth one, is heavier and shows the actual elevation
(1100, 1200, etc.).   You could, if you are nuts enough, measure the
horizontal distance along the car line and the vertical distance and come up
with an average percent gradient.

The green is forested areas.   Round equal spaced green dots represent
orchards.

Black squares are buildings.   A building with a cross on it . a church.

Black parallel lines are highways.   Main roads may have a red imprint.

Black cross-natched lines are, of course, railroads.

Dashed lines with dots after so many dashes . high voltage power lines.   

Blue . rivers and streams of course.    I forget the coding for intermittent
streams, those that dry up part of the year, but you will recognize it when
you see it.  

And if you have trouble opening the attached Glassport map, go here

     http://nationalmap.gov/historical/help/download_instructions.html

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On May 5, 2014, at 1:57 PM, Edward H. Lybarger wrote:

> I'm sorry...it's a gray line, not white.
> 
> -----Original Message-----
> From: pittsburgh-railways-bounces at mailman.dementix.org
> [mailto:pittsburgh-railways-bounces at mailman.dementix.org] On Behalf Of
> George W. Gula
> Sent: Monday, May 05, 2014 12:53 PM
> To: Pittsburgh Railways
> Subject: [PRCo] Route 56
> 
> It came across the old Dravosburg Bridge about 3/4 of the way, then left
on
> its own bridge and ramp to Maple Avenue, Elizabeth Road,
> Pittsburgh-McKeesport Highway to the Union Railroad overpass and private
> right-of-way. Google Earth stills shows the ROW at the horseshoe bend
below
> Lebanon Church Road. Then a new sewer project ruins it. Its hard to see
> where it went under Lebanon Church Road unless your right there because of
> all the erosion in the cut. Then straight through the Morton Plan to
> Buttermilk Hollow Road and a passage under another Union RR
Branch.\\George
> Gula
> 
> 
> 
> 
> 
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