jeffhergert tree68 BaltACD Recall hearing of a incident about a 'misunderstood' signal in the Chicago area, however, the indicent I recall was the Engineer operating the train through a set of crossovers at a higher speed than the signal on the incident railroad authorized because he had previously worked for another carrier where that specific indication authorized a much higher speed. I believe the entire train derailed, I don't know if fatalities were involved. Sounds like the same one. Don't think there were any fatalities - but the Amtrak loco did ride over a flatcar of some sort. I seem to recall that a change of legacy railroads on the Amtrak route was involved. The point being that one aspect can mean different things in different situations, such as this. I do like CPLs... I recall the Amtrak train rear ended another train or cars. Not sure of the crossover, but it makes sense as I recall the signal in question was red over yellow. Depending on rules in place it can be a Diverging Approach or Restricting. I recall the engineer read it as the Diverging Approach instead of Restricting. Jeff
tree68 BaltACD Recall hearing of a incident about a 'misunderstood' signal in the Chicago area, however, the indicent I recall was the Engineer operating the train through a set of crossovers at a higher speed than the signal on the incident railroad authorized because he had previously worked for another carrier where that specific indication authorized a much higher speed. I believe the entire train derailed, I don't know if fatalities were involved. Sounds like the same one. Don't think there were any fatalities - but the Amtrak loco did ride over a flatcar of some sort. I seem to recall that a change of legacy railroads on the Amtrak route was involved. The point being that one aspect can mean different things in different situations, such as this. I do like CPLs...
BaltACD Recall hearing of a incident about a 'misunderstood' signal in the Chicago area, however, the indicent I recall was the Engineer operating the train through a set of crossovers at a higher speed than the signal on the incident railroad authorized because he had previously worked for another carrier where that specific indication authorized a much higher speed. I believe the entire train derailed, I don't know if fatalities were involved.
Sounds like the same one. Don't think there were any fatalities - but the Amtrak loco did ride over a flatcar of some sort.
I seem to recall that a change of legacy railroads on the Amtrak route was involved.
The point being that one aspect can mean different things in different situations, such as this.
I do like CPLs...
I recall the Amtrak train rear ended another train or cars. Not sure of the crossover, but it makes sense as I recall the signal in question was red over yellow. Depending on rules in place it can be a Diverging Approach or Restricting. I recall the engineer read it as the Diverging Approach instead of Restricting.
Jeff
This one:
https://www.chicagotribune.com/news/ct-xpm-2009-04-01-0903310374-story.html
CPL's turn up in unlikely locations. I recall that a CPL was installed on the southbound CWI near 114th and Torrence in Chicago. It replaced a semaphore (!) about a half-mile further south. The new location provided more stopping distance for the absolute signal at the Calumet River drawbridge.
BaltACDRecall hearing of a incident about a 'misunderstood' signal in the Chicago area, however, the indicent I recall was the Engineer operating the train through a set of crossovers at a higher speed than the signal on the incident railroad authorized because he had previously worked for another carrier where that specific indication authorized a much higher speed. I believe the entire train derailed, I don't know if fatalities were involved.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
tree68... As Balt mentioned, one challenge these days is knowing which signal system you are operating under, as a given aspect may have different meanings on different railroads. This was the root cause of the Amtrak rear-ender some years ago in Indiana (or was it Illinois?), wherein the engineer essentially applied the wrong rulebook to a signal and ended up piling into the rear end of a freight.
As Balt mentioned, one challenge these days is knowing which signal system you are operating under, as a given aspect may have different meanings on different railroads. This was the root cause of the Amtrak rear-ender some years ago in Indiana (or was it Illinois?), wherein the engineer essentially applied the wrong rulebook to a signal and ended up piling into the rear end of a freight.
Recall hearing of a incident about a 'misunderstood' signal in the Chicago area, however, the indicent I recall was the Engineer operating the train through a set of crossovers at a higher speed than the signal on the incident railroad authorized because he had previously worked for another carrier where that specific indication authorized a much higher speed. I believe the entire train derailed, I don't know if fatalities were involved.
I am prejudiced - the B&O CPL's were the BEST of all signals. Didn't rely on a single bulb - visually commanding - the angled relationships of bulbs in the main signal head allowed even the color blind to correctly communicate signal indications.
Never too old to have a happy childhood!
BaltACD Jovet BaltACD On Dispatcher model board representations - the board only shows if a signal is (supposed) displayed - not the indication that the signal is displaying. The indication is controled by the ABS rules that are wired into signal systems. Depending upon route or track occupancy on the route lined, the indication displayed CAN be anything from Restricting to Clear and appropriate indications in between as dictated by the actual conditions and other train locations. Be careful throwing out "ABS" or "ABS rules" out there willy-nilly. The usual term is track conditions. Despite CSX's idiotic please otherwise, there are not ABS signals in CTC territory (for example). ABS - Automatic Block Signals CTC operates the Control Points - where switches and derails can route trains on multiple routes through the Control Point. Signals between Control Points operate on Automatic Block Signal rules. One other thing to remember - Today's Class 1's are operating, in many cases, with the LEGACY signal systems that existed on the 130+ Class 1 carriers that have been winnowed into becoming today's SIX major Class 1 carriers. BNSF CN CPKC CSX NS UP.
Jovet BaltACD On Dispatcher model board representations - the board only shows if a signal is (supposed) displayed - not the indication that the signal is displaying. The indication is controled by the ABS rules that are wired into signal systems. Depending upon route or track occupancy on the route lined, the indication displayed CAN be anything from Restricting to Clear and appropriate indications in between as dictated by the actual conditions and other train locations. Be careful throwing out "ABS" or "ABS rules" out there willy-nilly. The usual term is track conditions. Despite CSX's idiotic please otherwise, there are not ABS signals in CTC territory (for example).
BaltACD On Dispatcher model board representations - the board only shows if a signal is (supposed) displayed - not the indication that the signal is displaying. The indication is controled by the ABS rules that are wired into signal systems. Depending upon route or track occupancy on the route lined, the indication displayed CAN be anything from Restricting to Clear and appropriate indications in between as dictated by the actual conditions and other train locations.
Be careful throwing out "ABS" or "ABS rules" out there willy-nilly.
The usual term is track conditions. Despite CSX's idiotic please otherwise, there are not ABS signals in CTC territory (for example).
ABS - Automatic Block Signals
CTC operates the Control Points - where switches and derails can route trains on multiple routes through the Control Point.
Signals between Control Points operate on Automatic Block Signal rules.
One other thing to remember - Today's Class 1's are operating, in many cases, with the LEGACY signal systems that existed on the 130+ Class 1 carriers that have been winnowed into becoming today's SIX major Class 1 carriers. BNSF CN CPKC CSX NS UP.
In the last 30 to 40 years, some rules or their applications have been (in effect) "dumbed down." Some things have been simplified to "this OR that" instead of "this AND that." I have some old ETTs that show ABS over the entire subdivision and then where CTC is in efffect on that same subdivision.
JovetI know I'm an idealist, but it's a shame that the philosophy of the singaling system isn't learnëd on more employees. Studying the details of a signal chart tells how you that signaling schema ticks.
You learn what you need to do your job. If you're qualified on a territory, you'll know the signals you may see.
A fantastic example of this is B&O's CPLs.
A fully loaded CPL has eight lamps on the disk and six markers (3 above and three below). Fully loaded CPLs were rare (and even moreso now).
Instead, a given CPL only contains the lamps in the disk and the markers that are needed for a given location.
For example, the SE wye/transfer signal (for traffic going from WB to SB) only has one marker - the center bottom. That's because it can never show anything better than a medium clear or a medium approach.
The lunar that would occupy the upper left/lower right lamp locations in a CPL disk has been pretty much replaced. It would indicate restricting.
I usually tell folks that at its simplest, red is stop, yellow=approach, green=go. There are "always" three heads. If a head isn't there, it's the bottom (or bottom and middle), and is considered to be red. The top head is track speed, the center head is medium speed, and the bottom head is slow speed, all as defined in the rulebook.
Yes, there are all sorts of variations on the theme.
Fun for trivia nights and forums (or to bore a new conductor); pretty uselss for operations.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
BaltACDOn Dispatcher model board representations - the board only shows if a signal is (supposed) displayed - not the indication that the signal is displaying. The indication is controled by the ABS rules that are wired into signal systems. Depending upon route or track occupancy on the route lined, the indication displayed CAN be anything from Restricting to Clear and appropriate indications in between as dictated by the actual conditions and other train locations.
The usual term is track conditions. Despite CSX's idiotic pleas otherwise, there are not ABS signals in CTC territory (for example).
jeffhergertI don't think you should look at a flashing aspect as a modifier. It is just another signal aspect with it's own name and indication. Using a flashing indication allows more possible aspects and indications beyond the basic green, yellow and red colors.
But, that makes flashing versus steady a modifier. Steady is the more-common, so flashing is the modified variation. That modification is usually better than what it would be if it weren't flashing.
jeffhergertWhen looking at a particular railroad's signal chart, it does look a bit intimidating. Two things to remember about the charts. One is that an employee most likely will not see all of the combinations available. Depending on where one works, you might only see the basic block signal aspects and indications. The other is that working a territory regularly, you get to know the signals you see every day. It's rare to come across a signal that you haven't seen before. When we have signal changes, a bulletin or general order is usually given if there is a major change in what the signal can display.
I know I'm an idealist, but it's a shame that the philosophy of the singaling system isn't learnëd on more employees. Studying the details of a signal chart tells how you that signaling schema ticks.
ns145I have been told that flashing aspects were used for limited speed applications for the purpose of safety. If the mechanism producing the on-off flash effect fails, then the signal will revert back to a less favorable aspect with an indication for medium speed. That is, it would "fail safe". This principle seems to apply to most of the other non-limited speed flashing signal aspects that I have seen on different railroads too. For example, a flashing yellow Approach Diverging signal reverts back to a solid yellow Approach, a flashing Red Restricting signal would revert back to a solid red Stop, etc. It makes sense. Better for a train to stop or run slower than necessary than accidently tell it to run faster than what is safe.
This principle seems to apply to most of the other non-limited speed flashing signal aspects that I have seen on different railroads too. For example, a flashing yellow Approach Diverging signal reverts back to a solid yellow Approach, a flashing Red Restricting signal would revert back to a solid red Stop, etc. It makes sense. Better for a train to stop or run slower than necessary than accidently tell it to run faster than what is safe.
Just remember that flashing aspects can fail two ways: steady lit or steady dark.
The graceful and safe downgrade of a failed flashing aspect is definitely desired. It is not often that wrong-side failure is designed into a signal system, but it has happened. (Looking at you, N&W!)
Yes, I agree, assuming that they know that it's 'pumping'. My question was regarding the possibility of mis-interpretation. Think of a scenario with a single head signal where a red bulb is burned out and all the crew sees is the green bulb pulsing on and off as the signal switches between Proceed and Stop.
ns145 zugmann jeffhergert I don't think you should look at a flashing aspect as a modifier. Flashing for NORAC and NORAC-similar "upgrades" the signal. But the term is used mostly as a way to learn/remember the aspects. Red over green = medium clear. Red over flashing green = limited clear. Trivia: PRR used flashing aspects with their PLs, but they also retained an option of using a yellow triangle sign on the signal that upgraded the signal without the flashing. Only ever saw it on one signal (long gone). I have been told that flashing aspects were used for limited speed applications for the purpose of safety. If the mechanism producing the on-off flash effect fails, then the signal will revert back to a less favorable aspect with an indication for medium speed. That is, it would "fail safe". This principle seems to apply to most of the other non-limited speed flashing signal aspects that I have seen on different railroads too. For example, a flashing yellow Approach Diverging signal reverts back to a solid yellow Approach, a flashing Red Restricting signal would revert back to a solid red Stop, etc. It makes sense. Better for a train to stop or run slower than necessary than accidently tell it to run faster than what is safe. I do wonder, however, if it would be possible for a malfunctioning signal that is "pumping" to be accidentally interpreted from a distance as a more favorable limited speed aspect. The few "pumping" signals that I have personally observed looked like they were going nuts. Also, they were bouncing back and forth between Proceed and Stop aspects. That's definitely not right.
zugmann jeffhergert I don't think you should look at a flashing aspect as a modifier. Flashing for NORAC and NORAC-similar "upgrades" the signal. But the term is used mostly as a way to learn/remember the aspects. Red over green = medium clear. Red over flashing green = limited clear. Trivia: PRR used flashing aspects with their PLs, but they also retained an option of using a yellow triangle sign on the signal that upgraded the signal without the flashing. Only ever saw it on one signal (long gone).
jeffhergert I don't think you should look at a flashing aspect as a modifier.
Flashing for NORAC and NORAC-similar "upgrades" the signal. But the term is used mostly as a way to learn/remember the aspects.
Red over green = medium clear. Red over flashing green = limited clear.
Trivia: PRR used flashing aspects with their PLs, but they also retained an option of using a yellow triangle sign on the signal that upgraded the signal without the flashing. Only ever saw it on one signal (long gone).
I have been told that flashing aspects were used for limited speed applications for the purpose of safety. If the mechanism producing the on-off flash effect fails, then the signal will revert back to a less favorable aspect with an indication for medium speed. That is, it would "fail safe".
This principle seems to apply to most of the other non-limited speed flashing signal aspects that I have seen on different railroads too. For example, a flashing yellow Approach Diverging signal reverts back to a solid yellow Approach, a flashing Red Restricting signal would revert back to a solid red Stop, etc. It makes sense. Better for a train to stop or run slower than necessary than accidently tell it to run faster than what is safe. I do wonder, however, if it would be possible for a malfunctioning signal that is "pumping" to be accidentally interpreted from a distance as a more favorable limited speed aspect. The few "pumping" signals that I have personally observed looked like they were going nuts. Also, they were bouncing back and forth between Proceed and Stop aspects. That's definitely not right.
A crew that sees a signal that is 'pumping', by rule is expected to comply with the MOST RESTRICTIVE indication that the signal can display. Restricted at signals with a number plate and STOP at signals without a number plate.
Jovet MidlandMike Shouldn't there be a sign with the letter "A" for absolute if the signal is for the diamond. I don't see that, or a signal number which would indicate a block signal. In the era of PTC, is there no longer signage on signals? It sounds like you're thinking of Canada and how they roll. That is not how things are done in the US.
MidlandMike Shouldn't there be a sign with the letter "A" for absolute if the signal is for the diamond. I don't see that, or a signal number which would indicate a block signal. In the era of PTC, is there no longer signage on signals?
Shouldn't there be a sign with the letter "A" for absolute if the signal is for the diamond. I don't see that, or a signal number which would indicate a block signal. In the era of PTC, is there no longer signage on signals?
No, I'm thinking of U.S. Maybe it's more of an eastern thing, or a 50 year old thing.
jeffhergertI don't think you should look at a flashing aspect as a modifier.
I don't think you should look at a flashing aspect as a modifier. It is just another signal aspect with it's own name and indication. Using a flashing indication allows more possible aspects and indications beyond the basic green, yellow and red colors. While color light signals might sometimes have a fourth color (lunar white) on a signal head, a searchlight type signal can only display three colors.
While searchlights are being replaced, they are still out there in some locations. The lunar aspect also seems to be falling out of favor on some roads. It's being replaced with a flashing red aspect.
When looking at a particular railroad's signal chart, it does look a bit intimidating. Two things to remember about the charts. One is that an employee most likely will not see all of the combinations available. Depending on where one works, you might only see the basic block signal aspects and indications. The other is that working a territory regularly, you get to know the signals you see every day. It's rare to come across a signal that you haven't seen before. When we have signal changes, a bulletin or general order is usually given if there is a major change in what the signal can display.
On Dispatcher model board representations - the board only shows if a signal is (supposed) displayed - not the indication that the signal is displaying. The indication is controled by the ABS rules that are wired into signal systems. Depending upon route or track occupancy on the route lined, the indication displayed CAN be anything from Restricting to Clear and appropriate indications in between as dictated by the actual conditions and other train locations.
Jovet tree68 One thing I don't have down yet is the modifier that is a flashing head. What is confusing about that to you? Is there a specific situation you don't understand? Or is it the philosophy of flashing in the grand scheme of things?
tree68 One thing I don't have down yet is the modifier that is a flashing head.
One thing I don't have down yet is the modifier that is a flashing head.
What is confusing about that to you? Is there a specific situation you don't understand? Or is it the philosophy of flashing in the grand scheme of things?
Perry Babin The following site is basically what you posted but with different formatting. http://www.mikeroque.com/understanding-railroad-signals/
The following site is basically what you posted but with different formatting.
http://www.mikeroque.com/understanding-railroad-signals/
Yes, he has reposted portions of Mr. Krug's former webpages about signaling. It's the best explanaiton about "signals" that I've ever come across. If that doesn't make sense to you, feel free to ask questions.
Perry Babin As with most of railroading, some of my questions were answered here, others by searching. There are too many variations to have them all answered (or for me to know what all to ask). This goes for all of the rest of railroading. It's been evolving for a very long time so unless a very specific question is asked, the answer will likely be incomplete. Getting questions answered (for me) has been best if I have done enough research to have more than half of the answer. Then, I can be very specific and get an equally specific answer. This site has been very good. I also get answers from some YT channels.
As with most of railroading, some of my questions were answered here, others by searching. There are too many variations to have them all answered (or for me to know what all to ask).
This goes for all of the rest of railroading. It's been evolving for a very long time so unless a very specific question is asked, the answer will likely be incomplete. Getting questions answered (for me) has been best if I have done enough research to have more than half of the answer. Then, I can be very specific and get an equally specific answer. This site has been very good. I also get answers from some YT channels.
Signaling is a very complicated topic, especially in the United States. Personally, I find that envigorating, because the details fascinate me. As railfans, we're all always learners anyway. No one knows everything about railroading, not even the ones who are paid to do it.
Almost all US signaling system have some degree of roots in the basic system outlined by Mr. Krug. Some signal schemas have been more "corrupted" in that regard than others, but more often than not the differences are pretty minor.
Perry Babin For signals, I don't think I'll ever fully understand them. I think it would require posting photos of a specific signal on a track or set of parallel tracks and ask for all the possible signals and that's simply too much to ask. There are a lot of other things that interest me about railroading and I learn more each day.
For signals, I don't think I'll ever fully understand them. I think it would require posting photos of a specific signal on a track or set of parallel tracks and ask for all the possible signals and that's simply too much to ask. There are a lot of other things that interest me about railroading and I learn more each day.
Well, "fully understand" is pretty subjective. It depends on why you want to understand them. There are aspects of history, safety, mergers, technology, and operational efficiency to learn why signaling is the way it is. But, just learning what the signals in the areas you railfan can mean should be pretty straightforward. I don't know about you, but I like to know when a train is coming!
Oh wow, lots of replies here that it didn't tell me about. Ooops.
I was going to delete this but don't see the option. If it can't be deleted, you can see (barely) that the bottom head went from red to lunar then back to red. When it went back to red, the middle head went from red to green. This train was switched to the track that went to the right.
The signal changed from showing Restricting to showing Medium Clear. This area is pretty complicated, as it has two separate interlockings abutting each other (CP Rice, and CP Waycross Jct). Trains heading RIGHT here onto the Fitzgerald sub have to get switched through both interlcokings. The boundary on that connector track is a bi-directional absolute signal that protects both control points. It is only 1000 feet beyond the signal in the video, so this signal shows Restricting when that next signal shows Stop. Once that next signal is able to upgrade to Medium Clear or Medium Approach, this signal upgrades to Medium Clear. That is why there is no Yellow lamp on the second head—it's not needed. I do have a description of how this signal works on my short main signals page.
There's no reason for anyting other than the red on top because there will be no track speed at this location. << ?
And, yes, that's why there is only Red on the top: Track speed indications are not possible here, but the Red must still be there for the Medium and Slow speed aspects.
Does anyone know why they have all of the green lights in the railyard?
Those are switch point position indicators. The important and often-used turnouts in a big yard throat like this are still operated manually or semi-manually, but are often given local remote control by radio so crews don't have to waste time to stop to change them all the time. The indicators show the state of the switch: Green for "closed" or Normal (straight ahead), Yellow for "open" or Reverse (diverging), and Red for Error/Not Locked/Not Ready. The yardmaster may have direct control over setting up paths through the throat, and/or train crews can key special DTMF (touch tone) codes on the radio to change the switches. This saves a lot of time, and fuel.
It received a yellow on the bottom head and didn't move. Why didn't it move?
The train wasn't ready to move, or was waiting for a better signal indication so it wouldn't have to move a few thousand feet and stop again, blocking this level crossing and maybe others.
It then received a green on the bottom head and began to move. At about the same time, the gates came down and it crossed the road. What controlled the gates? It seems like the train position couldn't be used since it was already at the crossing.
Why didn't the gates come down on yellow?
The wayside signaling has absolutely nothing to do with the level crossing signals. With the exception of overlapping wiring circuits, they are completely separate things.
Almost all US and Canadian level crossing signals are fully automatic. Most grade crossings that are used regularly these days have a grade crossing predictor installed. What this does is it puts a special pulsed circuit on the track in both directions. The predictor will listen to the "sound" of these pulses as they go down the rails. If a train is present and shorts-out the rails (which is how track circuits all work), the predictor will hear this short out, and it can tell how far away the train wheels are from the crossing. It can tell if the train is moving towards or away from the crossing, and how fast it is moving. The goal is constant warning time for signals at the level crossing so that they activate a desired number of seconds (usually set to 20–40) before the train arrives, no matter how fast the train is going. If the predictor detects that the train has stopped moving towards the crossing, it will, after a delay, "time out" and turn the crossing signals off. It will turn them back on when it detects the train is moving again. This is very valuable in spots like this where trains often stop all over the place.
Does the yellow mean that only one block ahead was clear?
Does the green on the bottom head indicate that the next two signal blocks are clear?
Yes and Yes.
Railroad signal lights convey essential information: red means stop, green means clear to proceed, yellow signals caution, and flashing red indicates trains must stop. Additionally, flashing yellow signals an approach with caution, lunar white acts as a backup, and double red at a grade crossing warns of an approaching train.
timzOffhand guess: on any US railroad, "A" meant a dispatcher controlled signal, not a locally controlled signal. But many? most? RRs didn't bother with A's at all.
Not in the northeast. Only signals to have As on them were "approach restricting/approach clear" signals. Normally used when going from dark to signalled territory.
MidlandMikeShouldn't there be a sign with the letter "A" for absolute if the signal is for the diamond.
Offhand guess: on any US railroad, "A" meant a dispatcher controlled signal, not a locally controlled signal. But many? most? RRs didn't bother with A's at all.
jeffhergertOther than in pictures, mostly from years past, I've never seen an "A" plate on an absolute signal. Just the absence of a number plate. We have both "Restricting" and "Restricted Proceed" signals. The only difference is the Restricted Proceed is only on number plated signals. What, as already been referred to, is casually called an intermediate signal. There's no actual rule book definition of an intermediate, but everyone uses the term and knows what is being discussed. There are, or maybe were - I only know about the one I deal with, four locations on the UP where you can crossover on the indication of a single head signal. One is in Omaha where the Falls City subdivision (up from Kansas City) joins the Omaha subdivision. Where they join, a train going east on Omaha #2 or Falls City #3 will receive a single yellow (approach) if they will continue beyond on Omaha #2. If a crossover move for either is lined to go to Omaha #1, the train will get a single lunar (restricting). Until about 10 years ago, you could crossover on the yellow. The FRA made them change the aspects after a train that had been cleared through a Form B (work zone) only on #2 crossed over to #1. Back then, unless the dispatcher told you your route, you wouldn't know if you were going on #1 or #2 beyond that signal. They should've just replaced the signals with ones that could display a diverging aspect, but instead went the cheap route. Now with PTC engaged, you can see what route you will be taking. Jeff
We have both "Restricting" and "Restricted Proceed" signals. The only difference is the Restricted Proceed is only on number plated signals. What, as already been referred to, is casually called an intermediate signal. There's no actual rule book definition of an intermediate, but everyone uses the term and knows what is being discussed.
There are, or maybe were - I only know about the one I deal with, four locations on the UP where you can crossover on the indication of a single head signal. One is in Omaha where the Falls City subdivision (up from Kansas City) joins the Omaha subdivision. Where they join, a train going east on Omaha #2 or Falls City #3 will receive a single yellow (approach) if they will continue beyond on Omaha #2. If a crossover move for either is lined to go to Omaha #1, the train will get a single lunar (restricting).
Until about 10 years ago, you could crossover on the yellow. The FRA made them change the aspects after a train that had been cleared through a Form B (work zone) only on #2 crossed over to #1. Back then, unless the dispatcher told you your route, you wouldn't know if you were going on #1 or #2 beyond that signal. They should've just replaced the signals with ones that could display a diverging aspect, but instead went the cheap route.
Now with PTC engaged, you can see what route you will be taking.
Back in the day of double track being operated under current of traffic signaling Rules 251-252 the B&O at many tower locations had directional passing sidings, some were signaled and some were not. When lining a train into a unsignaled siding, the interlocking signal would display Restricting, the same indication that would be displayed when the train was being reversed against the current of traffic for its direction (when operating against the current of traffic the track IS NOT SIGNALED). The only indication that would tell the train the route, was the display of the Train Order Signal as the train required Train Order authority to operate against the current of traffic.
At this point in time most crossover and switches into passing sidings were all 10 MPH.
Other than in pictures, mostly from years past, I've never seen an "A" plate on an absolute signal. Just the absence of a number plate.
MidlandMikeShouldn't there be a sign with the letter "A" for absolute if the signal is for the diamond. I don't see that, or a signal number which would indicate a block signal. In the era of PTC, is there no longer signage on signals?
Most railroad rule books define an Absolute Signal as a signal without Number Plate. Signals with Number Plates are defined as Intermediate Signals. The most restrictive indication that an Absolute Signal can display is STOP. The most restrictive indication a Intermediat Signal can display is Restricting.
Back in the past, what is now known as Restricting on some carriers was known as 'Stop & Proceed'. A train size has grown, the carriers no longer want them to Stop and then Proceed at Restricted Speed - now Restricting permits the train to proceed at Restricted Speed without stopping.
Dispatcher or Control Operator's permission is required to pass an Absolute Stop Signal.
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