(erielack) Erie Signals

[JG at graytrainpix <graytrainpix_@_hotmail.com>]

> Many of the signal masts on the Erie NY Division were two 
> searchlight heads, the upper being on the right side of mast 
> and the lower on the left. As far as I can tell, these were 
> located on double or quadruple track at locations not having 
> Xovers, sidings or interlockings. What was the purpose of the 
> lower head?
My rough understanding of the rationale behind what you describe,
i.e. two-head automatic searchlight block signals, is that they allow
for “double approach” signaling.   (Recall, in Erie territory, offset heads are automatics; in-line heads are controlled signals, generally at switch interlockings, requiring absolute stop on red).  I.e., the 4 signals behind the
markers of a train will be stop & proceed (red-red), approach (yellow over
red), approach medium (yellow over green), and clear (green-red). 
With one-head signals, it would be stop & proceed – approach – clear -
clear.
  I'm not an expert on this, but I've heard that double
approach is desirable to space out trains, maintain safety factors
where block lengths are relatively short, and reduce stops by
following trains where train speeds vary significantly, e.g. due to
grades, curvature, intermediate interlocking plants, and “tasking”
(e.g., commuter local runs).  This obviously was desirable on the
higher-density commuter routes, or portions thereof. 

IIRC, the Erie
used double-approach between Jersey City and Rutherford Jct, on reversible 4 and 2-track TCS territory, mixed with one-direction ABS from HX to BJ Rutherford Jct. on 3 of 4 tracks.  From
there to Ridgewood Jct., both the Bergen County Line and the Main
Line were mostly single-approach signaled, double-track ABS territory.  Then from Ridgewood to
Suffern, an up-grade with WC interlocking in the middle, double-approach was common, with 4-track ABS. 

I believe there
was double-approach between Suffern and Newburgh Jct. also (double track ABS),  but
there may have been some single-heads too.  Between Otisville Tunnel
and Port Jervis I believe was also double-approach territory, given
the heavy eastbound grade (e/b track was ABS, but I think the w/b was reversible TCS).   




On the two APB lines, the Northern and
the NJ&NY, I recall that mostly single-head semaphores were used;
and thus the set-up was single-approach.  The traffic density and
relative flatness and straightness of those lines did not warrant
double-approach.  Interestingly, much DLW territory in New Jersey was
double-approach, as the standard DLW double head / four light system
allowed for approach medium. 

In 1964, when the EL linked the Boonton
Line west of Mountain View and Greenwood Lake Line, the former manual
block territory between Mountain View and Forest Hills Jct. was
signaled (double track ABS), and most of that was with double-head multi-light
signals allowing double approach.  That's not surprising given the
grades and commuter traffic that mixed with freight on this stretch.  (NJT
now used single approach here, but then again, there aren't any
freights mixed in anymore). 




That's a rough outline. I myself would
like to hear a more detailed analysis of the logic behind Erie and
DLW signal system design in specific territories. 

PS,  if you want something really rare, there supposedly were some 3-head automatic searchlights somewhere on the Erie!  I never saw one, but they allowed an indication called "approach slow".  See Rule 284.  (Didn't have anything to do with 3300 class steam engines -- I don't think so, anyway).


Jim Gerofsky


 		 	   		  
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