If you zoom in on the aerials of Rochelle
https://goo.gl/maps/MfJqLEg7Q6jpsSKx5
you can see there are no crossovers in the neighborhood (on UP anyway). A train on the UP approaching the crossing knows its route ahead is straight, with no need to slow down, assuming no trains ahead. A single green signal tells the engineer no trains are ahead -- no need for more info.
Perry BabinAssuming that these are single color lights (not searchlight type signals), how does it work with only one head (only for high speed indication?)?
That signal (its counterpart on UP is just below the diamond) is chiefly there to protect the diamond. You can see one BNSF signal tower alongside the rail park. The other is out of sight at the bottom of the image.
The Rochelle diamond is automatic - first come, first served. As such the UP and BNSF signals are interconnected (ie, interlocked). Occasionally, you'll see a train on one of the lines dawdle a bit in order to hold the diamond for another train on their line.
Since there is no routing to be done at this point, only one head is needed. Given a green signal (ie, it's OK to cross the diamond) trains can proceed at timetable speed. Remember that the other two signals in the stack are considered red, as they are not there.
The signals will also be tied into the regular lineside signals so they can convey the usual information about signals further down the line.
An interesting tidbit about Rochelle - although the diamond is 2x2 tracks, one of the BNSF tracks is, in effect, a long passing siding, beginning a few miles south of Rochelle and ending a few miles NW of the diamond (or vice versa, if you like).
Corrections gladly accepted!
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...
Assuming that these are single color lights (not searchlight type signals), how does it work with only one head (only for high speed indication?)?
The signal tower to the left of the untitled placemark is the signal tower (for reference to the track configuration).
It depends on circumstances why trains don't move, but instead wait for a more favorable indication. With a yellow, you would expect the next signal to be more restrictive, either a stop, stop and proceed, or a restricting. Waiting for the green means you won't have to stop or proceed at restricted speed into a possibly occupied block. Often taking the yellow could mean having to stop on crossings at the next signal for who knows how long. (Yes, we do try to avoid blocking crossings, or at least if we must, block the less important ones.) Waiting for the green, even when you have the Advance Approach before the yellow, means you have a little bit of room to run. In terminal situations it might not be much, but if you are out in the open, letting the guy ahead get some room for you may mean not having to slow down at every signal because you're catching up.
Most modern crossing circuits detect when movement begins. Many you can stop within a car length and the gates will time out and raise. When you begin to move, the circuitry senses the movement and activates the signals and gate. It can be a pain when circumstances require such a close stop and then beginning movement and waiting for the signals to activate. Usually such things happen when switching or setting out and picking up.
I had an unusual signal yesterday. They moved a block signal about a quarter mile, using a new signal. The signal is in advance of a 60 mph turnout. Usually, even when the signal governing the turnout is at approach or approach diverging, the old advance signal would give an advance approach indication. (For us, that's a flashing yellow over red on the old signal.)
Instead, the signal was a yellow over flashing red or Approach Restricting for us. PTC didn't indicate that the next signal was a Restricting nor that it was going to require restricted speed at the next signal. I was prepared for it anyway. We were going to stop at the depot about a quarter mile past the turnout anyway. It's not our normal change out point, but one for the long pool. Us short poolers usually go another 38 miles for our normal change out, but we only had about 10 minutes left to work.
PTC has really helped that you can "see" ahead of you. It indicates "targets" signals, speed restrictions, etc. 6 miles ahead, although the screen only actually shows about 5 miles ahead.
It helped me today to avoid blocking crossings, Some that have no other way in/out other than the crossings. We have a few places at my home terminal where we can change crews. The dispatcher never gave us any instructions as to where to change out. PTC started showing on the fringe that we were probably going to go into the siding. Once the actual control point controlling the route into the siding was on the screen, we weren't lined up past the signal. I immediately had time to take action to bring the train to a safe stop at the first change out point. Had I had to actually wait to see the wayside signals to figure out what was going on, I would've blocked half the town and some of those only access crossings.
Jeff
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.
Does anyone know why they have all of the green lights in the railyard?
Perry BabinIt received a yellow on the bottom head and didn't move. Why didn't it move? It then received a green on the bottom head and began to move.
The camera is pointed SW and the signal is at
https://goo.gl/maps/dUawVDHy2afXXLXe7
Another look https://goo.gl/maps/W35K9xUGXpoHGwGMA
First guess about the automatic crossing gates: they come down as the train approaches, but when the train stops short of the xing the gates will eventually rise. Dunno how the gates figure out that the train has started to move; maybe there's a trackside microphone so the engineer can sound the horn to re-lower the gates?
I know nothing about Waycross. If this train saw red over red over green, we can assume the next signal ahead is yellow or green, but he's probably not supposed to exceed 15-20 miles/hour for now.
By the way: in the US, "depot" means station building; that trackage ahead of the train is called the yard, except there probably is a track, called the main, that passes around the yard. If a train is headed for the main, maybe it will get a green on the top head of the signal. And maybe no such train has appeared for you. But you're looking down CSX's main line from the Northeast to Florida, so there must be a thru track that avoids the yard, and that's what the top head of the signal is for.
(I see now that the Folkston Cutoff still exists; no idea how many CSX freights use it instead of going thru Waycross.)
On the following, correct me where I'm wrong. This is at the entrance of the depot. Most trains go straight and only get a red on the top two heads and a lunar on the bottom.
There's no reason for anyting other than the red on top because there will be no track speed at this location. << ?
For the train below, it will not be going into the depot. Initially, it had a red bottom head light and stopped. It didn't get the lunar because it was not going into the depot. This track goes left at the switch. 31° 12.443'N 82° 21.671'W on google earth.
It received a yellow on the bottom head and didn't move. Why didn't it move?
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?
On a later train (19:45:30), the gates came down well before the train came into view and the train passes through the crossing on yellow, unlike they di previously.
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?
I don't know if these are archived but the date of the video was 2023-07-27 18:11:29. << easier to copy and paste if someone is going to search the archived file.
tree68I can't explain why there's red in the top position on a couple of the heads - you'd have to check the special instructions for that installation for that information. It could be that they don't have the usual green-yellow-red set-up due to special circumstances. Regardless - it's the color displayed by the head, not the color's position in the head, that counts.
Like this one here in my neighborhood:
https://goo.gl/maps/djWhLXACoMkLRQAT6
This spur is the remains of an ex-SOU line off Potomac Yard that is now an isolated chunk of NS that can only be accessed from CSX. It is out of service now, as the two customers are gone. The lower head has green, yellow, and red lights and the upper only red. Because of the track configuration beyond that signal, there was no purpose in being able to display most of the potential signal aspects. There was no need or purpose for a yellow over flashing green to mean "approach limited," so why stick a yellow light up there for no reason?
timzSo why the single top head, showing red? Apparently a train on that track has no full-speed route ahead of it, and red-over-green is the best it can hope for. In other words, the only route ahead of it is thru a 30?-mph switch.
One job where where I run, I come off a branch onto the main. Best signal that can be displayed is a slow clear. At that interlocking is a full sized, 3-headed signal - with the top head having only one light (red), middle having only one light (red) while the bottom head can display red (stop signal), steady yellow (restricting), flashing yellow (slow approach), or green (slow clear).
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
That would be my take.
The signal on the SW wye/transfer going out to the EW line includes a lunar in the middle head in order to be able to display a restricting. It's in the CSX signal rules.
tree68I can't explain why there's red in the top position on a couple of the heads
Most likely the single bottom head shows yellow or dark -- no need for it to be able to show red. Red over red over red means the same as red over red. I'm guessing the two-bulb bottom heads can light up green or yellow, or be dark.
So why the single top head, showing red? Apparently a train on that track has no full-speed route ahead of it, and red-over-green is the best it can hope for. In other words, the only route ahead of it is thru a 30?-mph switch.
Perry BabinAlso, the following is completely confusing. Red on top AND bottom with multiple heads and the bottom head is a single.
Easy peasy.
Each 'stack' is for a single track. The aspects that can be displayed will be covered in the railroad's signal rules. Here's CSX: https://signals.jovet.net/rules/CSX%20Signal%20Rules.pdf
These aren't searchlights - each lamp is a single color. At least that's my experience.
I can't explain why there's red in the top position on a couple of the heads - you'd have to check the special instructions for that installation for that information. It could be that they don't have the usual green-yellow-red set-up due to special circumstances. Regardless - it's the color displayed by the head, not the color's position in the head, that counts.
(Aside - There is one traffic light in Syracuse, NY where the colors are reversed. It's on Tipperary Hill, and as you might discern from the name, here is/was a heavy Irish component to the neighborhood. After several attempts to reset the light to the traditional red on top after local residents reversed it, the city gave up, so green is on top to this day.)
Any given signal will only have the heads necessary to display the aspects for that location. In the referenced image, the left signal will never display anything but red on the top head. That means that the signal will never allow a train to proceed at track speed. The right stack will likely have a modifier (lunar?) in the bottom head. Any unlit head is considered to be at its most restrictive aspect.
The bottom head on left and middle stacks have two lamps. Again, probably modifiers, but with two possibilities instead of one. Again, one would have to know the situation at that particular location.
This is why an engineer needs to know the rules as a whole, and his/her territory.
tree68 All that said - if you remember that red is stop, amber is approach, and green is go, as well as (in general) top head is track speed, middle head is medium speed, and the bottom head is slow speed, you're probably 90% there.
All that said - if you remember that red is stop, amber is approach, and green is go, as well as (in general) top head is track speed, middle head is medium speed, and the bottom head is slow speed, you're probably 90% there.
Deshler, OH (mostly CPLs, some "Darth Vaders" in view at times) and Leaman Place, PA (Strasburg RR - NE corridor with signals in the distance) are two I know of.
The cameras are handheld by YT channel owners. They sometimes tell the track owner or something like the XYZ sub but having that information AND the signals is rare.
For fixed cameras on sites like virtual railfan, can anyone recommend a camera location that shows the signals?
Perry BabinThe only times (for the most part) that I will see signals is in video (mainly from the US) and I generally have no idea who owns the tracks or signals.
If you're watching one of the current crop of rail cams, the description should fill you in on which railroad you are watching. With run through power as common as it is, however, it's sometimes a challenge to figure out who's who just by watching the video stream.
Older videos usually tell who's who as well.
Certain railroads had characteristic signals, a la B&O's color position lights (CPLs). It takes a while to figure all of them out, though.
Perry Babin... and I generally have no idea who owns the tracks or signals.
While MOST railroad signals are lit with incandescent light bulbs - LED lit lights have a definate FRAME RATE, wherein the the LED cycles many times a second. Many of the video cameras in use today, also have a frame rate in capturing their images. The situation can develop where the frame rate of the camera and the frame rate of the LED go into and out of sync - some times you see the light, some times you don't.
In the following video notice how the crossing flashers show up for a period of time and then disappear for a period of time. With my eyes viewing those flasher, both of them flashed continuously for the duration the included the video clip.
Never too old to have a happy childhood!
Perry Babin The signals are hard to see in videos because the camera adjusts for the majority of the image and not the signal itself. Add to that that some of the signals have lenses that produce a beam designed for viewing at the engineer's position, inline with the tracks and well above ground level.
The signals are hard to see in videos because the camera adjusts for the majority of the image and not the signal itself. Add to that that some of the signals have lenses that produce a beam designed for viewing at the engineer's position, inline with the tracks and well above ground level.
The signal heads actually have a sighting system built in so they can be aimed at the point where the crew needs to see them. Nothing fancy - think "iron sights" on a rifle.
You can see that in play on the southwest wye/transfer at Deshler. During the day, it can be very hard to see that signal from the webcam, since it's pointed so the incoming trains can see it.
My observation of most railroad videos, foreign and domestic, it is very difficult to even see the indications being displayed.
One thing I learned from riding the head end of trains during my 51 year railraod career - YOU HAVE TO KNOW WHERE TO LOOK, when it comes to looking for signals, especially when you are riding trains through urban areas - railroad signals have to compete with all forms of lights that exist - traffic lights, street lights, advertising lighting - you name it. If you don't know where the signal is and what it is supposed to be displaying or you can miss it.
The only times (for the most part) that I will see signals is in video (mainly from the US) and I generally have no idea who owns the tracks or signals.
I appreciate the input (even when it may not directly apply to the original question) because it fills in a lot of blanks and makes me think outside my original assumptions.
I will continue to pick up on fine details for as long I continue with this interest (likely for a long time). Sometimes interest is lost when I feel I've learned everything (as much as I want) about a topic. That will never happen with railroads and trains. The more I learn, the more I realize how ignorant I am about the subject.
Perry BabinFor signals, I don't think I'll ever fully understand them.
First thing to do: figure out whether the RR you're looking at is route signalled or speed signalled. Without that, you'll never understand the signals. If you tell us what piece of RR you're wondering about, maybe someone knows the answer.
wjstixThe meaning depends too on what system the railroad uses - ABS or CTC or what. Traditionally, two or three head signals were used at interlockings, so say green-over-red meant you were continuing on the mainline while red-over-green meant you were going onto a branchline or taking a siding or going onto some other secondary trackage. In this case yellow-over-red would normally mean you were continuing on the mainline, but at reduced speed - possibly meaning the track block ahead was clear, but the next one was occupied. It could also mean speed was reduced for some other reason related to what's ahead - coming to a station or yard, reduced speed due to a sharp curve, etc.
Signals indicate what's in the rule book. For example, under NORAC, a "green over red" is a clear signal and is rule 281: "proceed not exceeding normal speed". That is it. Usually it means you are staying with the main, but you have to be careful looking for deeper meaning when it isn't there (on paper).
And if you get an approach on NORAC, the block ahead of it better be clear, or we need a maintainer.
zugmann PNWRMNM Absent more info we do not know why the yellow is displayed on the top head. Mac Usually, a 2-headed automatic (intermediate) is the signal that comes before an interlocking - sometimes referred to as a "distant signal". So you have there an approach signal, which means: proceed, prepared to stop at the next signal.
PNWRMNM Absent more info we do not know why the yellow is displayed on the top head. Mac
Usually, a 2-headed automatic (intermediate) is the signal that comes before an interlocking - sometimes referred to as a "distant signal". So you have there an approach signal, which means: proceed, prepared to stop at the next signal.
BaltACDAction on CSX Old Main Line
He's trying to find a steam engine.
Too soon?
Action on CSX Old Main Line
https://www.youtube.com/watch?v=8uKqhSTOg_4
It may be a bit dated, but I have found that my copy of "All About Signals" is still useful in providing the basics. With an assist from a couple of "Rules for Conducting Transportation" in my collection, I can read most signals reasonably correctly.
What can get interesting is figuring out the situation with reverse signalled track governed by CTC.
Perry BabinFor 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.
That is perhaps the beauty of B&O's old color position lights (CPL's). While there was a specified full complement of lights included by the system, in reality specific installations only had the light heads that were needed.
You can read all about them here: https://railroadsignals.us/signals/cpl/index.htm
Most railroads' signals are somewhere on the web. You'll find that while there may be some different configurations, and the rule numbers are specific to each railroad, but in the end the meanings are very similar.
If you follow a specific railroad, concentrate on learning their system.
One thing I don't have down yet is the modifier that is a flashing head.
Jovet It's always nice to see a good railroad signaling thread on sites like this. Was your question answered? There are two main types of questions I get about US railroad signals: What does the signal I'm staring at mean? What? How does this system make any sense? For #2... The system, generally, does make sense. But it's not a system most people (even railroaders) are going to just work out for themselves. Al Krug did a great job explaning the general basics. Unfotunately his site disappeared, but an archive of it is available here. It's a great read for anyone wanting to understand US railroad signaling. EAch railroad may have a slightly different signaling schema, but the basic concepts are pretty standard. Railroad signaling is a complex and detailed topic, which is probably why I like it so much. I also find it fascinating how little 8-inch lights can tell a 20 million pound train what to do.
It's always nice to see a good railroad signaling thread on sites like this.
Was your question answered? There are two main types of questions I get about US railroad signals:
For #2... The system, generally, does make sense. But it's not a system most people (even railroaders) are going to just work out for themselves. Al Krug did a great job explaning the general basics. Unfotunately his site disappeared, but an archive of it is available here. It's a great read for anyone wanting to understand US railroad signaling. EAch railroad may have a slightly different signaling schema, but the basic concepts are pretty standard.
Railroad signaling is a complex and detailed topic, which is probably why I like it so much. I also find it fascinating how little 8-inch lights can tell a 20 million pound train what to do.
The following site is basically what you posted but with different formatting.
http://www.mikeroque.com/understanding-railroad-signals/
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.
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.
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