"*" Modern "*" Signalling!!!!!!!

[Jim Holland]

Greetings!

	In the Drake article by Chris Potter (http://www.pghcitypaper.com/newz1.htm) the third 
paragraph from the end talks about signalling and is quoted here:
	"But keeping the Authority's three operating trolleys up and running would cost upwards of 
$1 million just for the next two years, says Grove. The problem is especially pressing as the "T" 
switches to a new signaling system the PCCs aren't compatible with. `You'd almost need someone out 
there giving hand signals,' Grove says."
	Everyone here is familiar with South Hills Junction - yes?!  Cars southbound exiting the 
tunnel split into two different main directions.  Within the wye formed by these two trunks is a 
loop and inside the loop is a beautiful admin building not unlike a small town mainline railroad 
station.  The track behind the admin building crosses one trunk to join a branch from that trunk 
which immediately branches.  And immediately after this is the main yard lead for a very large yard! 
 Yet the only "*" signalling"*" here is for the two inbound derail switches and the switch exiting 
the tunnel southbound - everything else was done *by sight!*  Imagine trying to get through this 
maze with modern "*"signalling"*" - it would probably add at least 10 minutes running time one way!
	In an evening rush hour in 1950,  a-l-l  cars returning to the barn would have to loop the 
admin building and then cross the interurban lines to join the 38, 39, 40, and 42 lines outbound to 
enter the yard!  That means the interurban trippers to West Library, Riverview, Canonsburg, and 
Castle Shannon along with hilltop routes on the 44, (47), and 48, as well as the 38, 39, 40, 42, and 
(43) would compete for space on this loop as well as right-of-way to cross the interurban lines and 
join the yard lines briefly.  All of this was done by sight.
	I can't say that this system was problem free nor without accident, but it worked extremely 
well for many decades!
	Here in San Francisco they installed a double scissors crossover on either side of the 
high-level platform stop for San Francisco State on the M OCEAN VIEW line.  This location is 
center-of-the-highway prw.  What a farce getting through the interlocking.  There are also two grade 
crossings associated with the scissors on the outbound side of the platform and these are controlled 
by traffic signals.  The interlocking increases the running time here by two traffic lights and is 
problem prone!
	So much for "*" Modern "*"  Signalling!!!!!!!

-- 
James B. Holland
       PITTSBURGH RAILWAYS COMPANY (PRCo), June of 1949 -- June of 1953
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