RE: (erielack) Signal question - East Lincoln Park

[Gordon Davids <g.davids_@_verizon.net>]

Paul and all -

A few more details about East Lincoln Park that might be useful.  I 
don't want to appear picky, but the term "aspect" applies to the 
appearance of the entire signal as seen from an approaching train.  The 
collection of lamps or lenses in one sheet metal background is still 
termed an "arm," dating from semaphore signal days.  So I think we are 
discussing the bottom lamp of the top arm of the eastward signal from 
Lincoln Park siding having been blanked with sheet metal.  The lamp 
would have been removed because it was no longer used in any of the 
aspects displayed by the signal.  The hole in the background would be 
blanked to prevent sunlight or other light from passing through the 
target and giving a false indication.

The best indication that the siding signal could display in 1975 was 
"Clear Medium," Red over Green, because the diverging route (even though 
it was trailing through the switch) was limited to Medium Speed.  So the 
top arm always displayed a red lamp.  By itself, with no lamps lit in 
the bottom arm, it indicated "Stop."  When the bottom arm displayed a 
green lamp, the indication was "Clear Medium," Red over Green, and when 
the bottom arm displayed yellow, the indication was "Restricting," Red 
over Yellow.

The eastward signal governing the route from the main track retained the 
two lamps in each arm because it displayed aspects for a normal speed 
route.  The single Red (top arm) aspect indicated "Stop." Red (top arm) 
over Yellow (bottom arm) indicated "Restricting." Single yellow (top 
arm) indicated "Approach."  Yellow (top arm) over Green (bottom arm) 
indicated "Approach Medium," and single Green (bottom arm) indicated 
"Clear," unless . . (see below).

I don't recall the indications of the eastward signal at Mountain View.  
The curve itself from the Boonton Branch to the Greenwood Lake Branch 
was limited in the time table to 30 mph.  I don't remember if the best 
indication on the eastward home signal was "Medium Clear" or "Clear;" 
that is, if EL covered the speed restriction simply in the time table, 
or if it was also enforced by the signal indication.

Good signal practice calls for the latter.  If that was the case, and if 
the eastward signals at East Lincoln Park governed the approach to 
Mountain View, then the best indication on the main track signal at East 
Lincoln Park could have been "Approach Medium," Yellow over Green, and 
on the siding signal, "Medium Approach," Red over Flashing Yellow.  
Also, in that case, the bottom arm of the siding signal would have 
needed only a single yellow lamp because there was no green in any of 
the aspects.

The DL&W and EL were the only railroads I have ever seen that included 
non-illuminated arms in legitimate aspects.  The yellow top arm, when 
illuminated over a green bottom arm, downgraded a signal indication from 
"Clear" to "Approach Medium." Also, the red top arm in an interlocking 
home signal downgraded a "Clear," single bottom arm Green, to "Clear 
Medium," Red over Green.  If the illuminated top arm was obscured by a 
bird nest or anything else, the signal could display a false clear 
indication.

When I (as a Track Department guy) expressed my displeasure over that to 
our signal supervisor, he told me that they used light-out relays to 
protect against that.  But of course a relay doesn't protect against a 
physical obstruction obscuring the lamp.  I always considered that a 
violation of the fail-safe principle.

Just another $0.02.

Gordon Davids

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