N&W a "Party" to PRR Lewistown Cab Signal & Train Control Tests in 1923

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The Gubbmint's big 1920s "train Control" fiasco/boondoggle occupies much of
the signal literature of that decade.


And thus it is that the July 1923, issue of Railway Signal Engineer (vol.
16, p. 288) carries a several-page listing of which form of train control
the various roads had chosen, and on which territories it would be
installed.


The entry for the Norfolk & Western is very interesting, to wit:
"Territory on which installation is to be made, not specified.  Device
Selected:  This road is a party to tests being made of Union Switch &
Signal Co's device on the Lewistown Branch of the Pennsylvania RR."


The branch on which the referenced "tests" were conducted was the Sunbury &
Lewistown Branch, 50 miles long, in Pennsylvania, some of which is still in
service.  It was in these tests that the first cab signals were tested and,
as part of the test package, electro-pneumatic equipment was included which
would apply the brake if an engineman exceeded certain speed thresholds
imposed by cab signal aspect.  The principles of coded track had not been
invented at this time.  The first experiments used a principle called "loop
and track currents," by which two AC currents were present along the track
and, depending upon whether these two currents were in-phase or
out-of-phase with each other, the cab signal responded in different ways,
employing inductive pick-up.  The experiments lasted over two years and
were the subject of a number of articles in the technical trade press.  The
NRHS Library in Washington holds a number of original photographs taken
during the tests.


I would love to know the agreement by which the N&W was "a party" to the
tests, which N&W personnel participated and what reports they filed.


Attached is a PDF-ized  article which appeared in Railroad Magazine in
1952, describing the tests.  It is a "popular" and human-interest type
article, not a technical one.  If you wish to know how the equipment
worked, you must go to Railway Signal Engineer magazine.


(PS - When the N&W made its first cab signal and train control
installation, on the north end of the Shenandoah Division, sometime around
1926, they used the old "track and loop current" technology which was
worked out at Lewistown.  Every time I look at the circuits, the word which
comes to mind is, "Nightmare."  It is a wonder they ever kept all the
variables in adjustment.  But those old guys got the job done, using what
they had.  The cab signals between Shenandoah and Roanoke, installed later,
operated by a different principle.)


-- abram burnett,

      defendant


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https://www.nwhs.org/mailinglist/2018/20180719.PRR_Early%20Cab%20Signals__Schnure__Railroad%20Magazine_Oct%201952_rev%207-19-2018.pdf
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