What is the meaning of a signal that is completely dark, with the red just not even being lit up? I thought for the most part such signals were new parts of the signaling system that have been installed but not activated yet - but now I think I may be wrong. Also, for signals installed but not activated I though that they had to have their hoods pointed somewhere other than down the tracks since they were not active - is that correct or not?
any active signal that is “dark” is an automatic stop.new signals are usually turned or have bags on them until they are activated.
stay safe
Joe
Sawtooth500:
Basically “stop.” Further actions are dependent upon what type of signal it is.
UP’s West Colton Yard in Southern California had an absolute signal (photo center) that for a while seemed to be lit activated from some unknown source.
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In the above photo, the “dark” signal has a “BEGIN CTC” lower sign reflecting; and the yellow and green lights are ground yard switch position indicators.
Then there are UP derail activated signals with simple wiring for departing certain tracks and entering the mainline.
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If a signal has two heads and both are dark with a train in front of it and without a logical explanation, it could be a faulty situation, but that would be short lived for sure.
It is hope the above gives you, Sawtooth500, at least some possibilities that might answer your question.
K.P.
I’ve seen signals in SE Arizona on the Union Pacific Sunset Route that turn off when there are no trains within a certain distance. I think this is a power saving mode since most of them have solar panels.
Yes, those are “approach-lit” signals. They’re dark unless there’s a train approaching them (if you know your territory, that’s as good an indicator as any). I forgot where we were recently, and was surprised by a signal going out after the train had cleared (it had changed to red, of course, as the locomotive went by, but as soon as the block in advance of the signal was cleared, it went out completely). I think that absolute signals stay lighted no matter what, though.
Home and interlocking signals and some approach signals will stay lit all the time. But automatic block signals may be approach lit, i.e. when an approaching train enters the preceeding block. Some will go off after the train leaves the block others after entire train enters the block and is past the signal. In some systems on single track signals will be dark in both directions until approached, others will be set and may be lit by dispatchers’s direction of traffic control; others will be on in both directions all the time. Check NORAC rules and rules of your local railroad for full understanding.
There’s lots of home and interlocking signals that are approach lit as well.
No sir. Most of the absolute signals on the Class Is I have worked for (which encompass more than half of the U.S.) are approach lit, regardless of what they authorize or where they are located. The typical reasons for not using approach-lit signals are as follows:
- The railway wanted to provide information about train movements to track cars or track inspectors (an obsolete reason now).
- It was infeasible to provide a circuit to light the signal sufficiently in advance to provide a safe braking distance for a train due to the proximity of track features such as switches and derails.
- There are no track circuits – this is commonly seen in fixed approach signals for drawbridges and interlockings in territory not operated under signal indication.
- The signals were arranged on the overlap principal or several other now obsolete schemes.
Prior to WWII there were all sorts of variations from practices we use today. There were several types of poor man’s APB and CTC that used constant-lit absolute signals because there were no track circuits between the control points. For example, portions of UP’s Kansas Pacific line used a low-cost arrangement that placed absolute signals at siding switches for the main track only, with an approach signal about 2 miles out that provided information only about the condition of the absolute signal. In this system all the signals were constant lit because there were no track circuits. While virtually all of these legacy systems are long gone as far as being continuous installations, there are often remnants of them within current-day CTC and APB systems.
RWM
Signals that are not within a block signal system, such as within yards, are not governed by block signal system rules. These signals have no requirement whatsoever to comply with typical practices seen on main tracks. As long as the signal’s aspects and indications, or the absence of aspects, are described within an operating rule such as a timetable, general order, or bulletin, they can be and do anything anyone might want. A signal that governs entrance to a block signal system, such as governing train movements from a departure yard to a main track, is part of the block signal system.
A faulty situation is the least likely explanation. Typically the signal is dark because the train has not yet entered the approach circuit (the “Ring 10”). Sometimes these approach circuits are very short because otherwise the approach circuit would be improperly activated by switch engines, standing cars, or reversed turnouts within the yard, which would then lock up main track movements. In other cases the signal is a “call on” signal activated by a control oper
The derails don’t normally activate the leaving signals. There is an approach circuit that lights them up, just like ones on the main line.
An imperfectly displayed or absent signal is to be regarded as giving it’s most restrictive indication. An Absolute signal would be Stop. A block signal with a number plate would be Stop and Proceed or (for those who’ve done away with S&P) Restricted Proceed.
The Control Points on my territory run the gamut. There are those that are constantly lit. Some that are approach lit where all the Absolute signals, no matter what track, light up. Some that are approach lit where only the signal(s) for your route light up, the rest stay dark.
Jeff.
Not necessarily. Grade signals, for example, might light only when there is a train in the block ahead. As for signals that have been inactivated or are not yet activated, you’re correct, they must be obscured or aligned so that there can be no possibility that they can be confused with active signals in a territory operated under signal indication, or as active signals in a territory not operated under signal indication, unless a general order or track bulletin is issued instructed train crews to disregard the signal, or a general order or track bulletin has been issued that discontinues signal operation between certain limits. For example, when new signaling is being cut-over within CTC territory, typically a general order is issued that “discontinues CTC” within the limits of the cut-over. That enables the signal gangs to properly align and test the signals during the cut-over, without completely stopping the railroad’s traffic and its revenue stream.
RWM
I took what K.P. meant to be something as simple as a burned-out bulb - which would also be rare.
RWM’s mention of “a particular signal at an idiosyncratic location” brings to mind the exact opposite - there was a “ghost signal” at Lehighton, PA which was always lit even though there’s no track in front of it anymore. It was part of a complicated junction between the LV and CNJ, and supposedly it was just easier to maintain it “as-is” than to rewire the circuit to do away with it - but apparently in March 2009 it was finally disconnected as part of a general signal upgrade/ replacement by NS in the area. See the following, listed in order of quality:
http://www.railroadforums.com/forum/showthread.php?t=20983 - links to 3 other threads in this one
http://american-rails-forums.com/viewtopic.php?p=13919&sid=ee0e75315b099a6598cc9ee84bfdd5af
- Paul North.
More likely that it was easier to maintain the signal than it was to wrangle with the FRA to discontinue the signal. The rewiring part is straightforward.
RWM
As I often point out each railroad is different either wholly or in different places and at different times; often times because of inheritances from mergers. Everything I said here is true to many different locations and operations I have seen over the past 60 or so years. Everyone who has contridictedd me is equally correct in what they have said. The most important thing I noted was that a truth for a given location, given railroad, given system is found in the employees timetables and books of rules for that given railroad; these are different for the railroads in Portland, OR, Portland,ME, Portland, PA, or anyother Portland.
The ICC now FRA approval to discontinue signals is the hard one. I worked the B&O’s WS Tower at Watson, IN in the late 60’s. WS was the junction of the B&O lines to Louisville, Jeffersonville and North Vernon, additionally the PRR crossed over the various lines to gain entry to the Charlestown, IN Ammunition Depot (a big deal in WW II). The PRR signals had to remain operative and lit even though there were 18 inch diameter trees growing within the gauge of the PRR tracks. The ICC would not let the PRR abandon the trackage and would not permit the B&O to discontinue maintenance on the PRR signals within the limits of the plant.
[quote user=“Railway Man”]
Paul_D_North_Jr:
I took what K.P. meant to be something as simple as a burned-out bulb - which would also be rare.
RWM’s mention of “a particular signal at an idiosyncratic location” brings to mind the exact opposite - there was a “ghost signal” at Lehighton, PA which was always lit even though there’s no track in front of it anymore. It was part of a complicated junction between the LV and CNJ, and supposedly it was just easier to maintain it “as-is” than to rewire the circuit to do away with it - but apparently in March 2009 it was finally disconnected as part of a general signal upgrade/ replacement by NS in the area. See the following, listed in order of quality:
More likely that it was easier to maintain the signal than it was to wrangle with the FRA to discontinue the signal. The rewiring part is straightforward.
RWM
As well as constant lit and approach lit signals, there were also “lined lit” signals. These would light up when the dispatcher cleared the route for a train, which might still be 20 miles away. This may have been a feature on mid-60s installations, since they seem to be vanishing as the electronics get upgraded.
While energy savings can be a factor in having the signals light up only when necessary, another advantage is the prolongation of bulb life. A burned out bulb means the signal is improperly displayed and has to be treated as if all the heads (even lit ones) are red. Call out the signal maintainer on overtime if you want to keep the railroad fluid!
On lines with heavy traffic you are more likely to find the signals, especially at control points, are lit all the time. Additional logic is required in the signal circuits to turn the lights on and off, and that may not be justified by a minimal extension of bulb life.
John
Somewhere in my photo files I THINK there is a shot taken in either Taylorville or Pana, Il of the abandoned B&O line to Springfield (thinking it was Taylorville).
A B&O color position light signal was burning brightly (green) even tho the tracks were pulled.
Ok…so is that possible? or is my memory giving false signals? This would have been in the early 90’s.
Balt…also back in the 90’s I made an overnight trip to Louisville and stayed on the Indiana side. It was summer and it was a gorgeous summer evening. I stumbled onto Watson Tower and explored it. Of course if was abandoned, but the brick tower looked great. I even went inside and took shots of the armstrong levers.
At the time there was a sort of semaphore signal at the crossing, no doubt governing the movements at the location.
Does anyone know if Watson is still standing?
Ed
Along the same note, there was a crossing through a 4 lane road in my town that had gates, red flashers, and crossbucks. The tracks were removed but the rest was left for years. Of course an “exempt” sign was hung for the school busses. Now 10 years later the gates and lights are gone (probably in some kids bedroom) but the posts, crossbucks and “exempt” sign are sill there. I wonder if federal law requires a school bus to stop at a crossing even if there are no tracks within 3 miles?
Still standing in November 2009.
WP’s CTC, built in the late 1940s and early 1950s, was “lined lit,” as you call it. When the dispatcher selected a route for a train, and hit the button to send the code out, the signals would light up. This was a safety feature to alert track maintainers. It was very dramatic at night to see 25 miles of signals light up like a Christmas tree across a dark desert basin. This concept was of particular value for WP because it had very few train movements per day – about five each way – meaning that track and signal maintainers were typically in the business of not expecting trains.
The additional logic required to have approach-lit signals in a relay-based system is not a significant added complexity. In a microprocessor-based system, it’s basically not much more than selecting some toggles in the software design. Some railroads used to like to use constant lit signals just for the added safety it provides for men on