Signals Question

[DC Railfanner]

What is the use of having single red lights at the very bottom of a set of signals. Being a CSX fan, this has always confused me as they don't have them. Thanks!

Example: http://www.railfanguides.us/sc/blacksburg/groverall.jpg" onclick="window.open(this.href);return false;

[Wayside]

What is the use of having single red lights at the very bottom of a set of signals. Being a CSX fan, this has always confused me as they don't have them. Thanks!

Example: http://www.railfanguides.us/sc/blacksburg/groverall.jpg" onclick="window.open(this.href);return false;

The extra signal head is there to allow for more aspects to be displayed at the location in question, such as a restricting, which is two reds over a bottom yellow.

But now that I actually click through to your link, I see you are asking something else. The signals you show are actually able to only have two lights burning at a time. The top three are red/yellow/green lights. The picture is actually of a location where it appears the signalmen are taking down the the two signals and their supporting signal bridge after having installed the two alongside the tracks.

[DC Railfanner]

What is the use of having single red lights at the very bottom of a set of signals. Being a CSX fan, this has always confused me as they don't have them. Thanks!

Example: http://www.railfanguides.us/sc/blacksburg/groverall.jpg" onclick="window.open(this.href);return false;

The extra signal head is there to allow for more aspects to be displayed at the location in question, such as a restricting, which is two reds over a bottom yellow.

But now that I actually click through to your link, I see you are asking something else. The signals you show are actually able to only have two lights burning at a time. The top three are red/yellow/green lights. The picture is actually of a location where it appears the signalmen are taking down the the two signals and their supporting signal bridge after having installed the two alongside the tracks.

I know that the signals are undergoing replacement. What I was confused about was the bottom head on all signals pictures only has the ability to display a red. Therefore, to my knowledge, the only aspects that can be displayed are clear, approach, or stop (there may be more, I'm not an expert on NS aspects) whereas if a head that could only display a red was placed on top it would create medium/limited (diverging on NS) aspects (ex: diverging clear). I was wondering what role a head with a single red on the very bottom plays.

*EDIT: I FOUND OUT THAT THE ALWAYS RED ON THE BOTTOM SIGNALS THAT A MAINLINE ROUTING CAN BE TAKEN OVER THE TURNOUT. BOTH TRACKS HAVE THIS IN THE IMAGE BECAUSE THE SWITCH PAST THE SIGNAL IS A "Y" SWITCH, NOT A STANDARD TURNOUT USED IN A SIDING.

[Wayside]

okay yup

NS signals:
http://signals.jovet.net/rules/NS%20Signal%20Rules.pdf

[bostontrainguy]

Haven't seen signals placed like this before. Anyone have any idea of what's up with this? It's on CSX's S Line in Florida.

Obviously a train in the right track would block the signal for trains on the left track. Doesn't make sense to me.

IMAG2561.jpg (959.83 KiB) Viewed 4829 times

IMAG2562.jpg (523.48 KiB) Viewed 4829 times

[Jovet]

What is the use of having single red lights at the very bottom of a set of signals. Being a CSX fan, this has always confused me as they don't have them. Thanks!

This thread is a bit old, but the correct answer has yet to show up.

The extra reds are there to re-enforce that the signals are absolute signals—a stop and stay is required. NS has a policy that all absolute signals must have at least two red lights, to make sure the signal is still observed in case one of the red lamps should fail. Permissive signals may have only a lone red light if multi-head aspects are not required on the signal.

CSX surely has the same policy, but you seldom see 1-lamp red signal heads on their newer signals because CSX's signaling schema makes it more likely to show multi-headed aspects, as well as CSX's common policy to allow a Lunar White aspects to be available on absolute signals for fleeting/call-on.

[docsteve]

CSX uses single head signals between interlocking distant signals, which are themselves multi-head automatics. Interlockings usually have three heads, which provides for a slow or restricting signal.

BUT, what I find interesting about the NS signal card is that new installations are Southern legacy, so no NORAC. Looks like the railroad should have been named Southern Norfolk.

[fcqjx]

...

BUT, what I find interesting about the NS signal card is that new installations are Southern legacy, so no NORAC. Looks like the railroad should have been named Southern Norfolk.

Actually the NORAC signal aspects have been continued in ex-Conrail territories (with some modifications), just with the new standard Safetran signal heads (and they still are using incandescent bulbs, no LEDs). In cab signal territory they are removing almost all intermediate signals (they left 4 in Altoona) and running by cab signal only between Control points. The Control Point signals there have "C" lights to allow trains with cab signal failures to run. In ex-Conrail territory you will still have speed signals at Control points ("medium clear", "limited clear") while in ex-Southern and N & W territories you'll hear route signals ( "diverging clear").