Canadian signalling - how does it work?

[dibber25]

...and please don't say "by electricity." Try as I might, I can't get my head round the Canadian signalling system. I appreciate it is similar to our Absolute Block System but it's the actual trackside indications that i don't understand - the different colour combinations that seem to mean different things. For instance, they don't seem to have 'feathers' on their signals so how do you tell if its a junction signal and if you are going to diverge at the next turnout? Is there a sequence of warning signals, and if so, what aspects would they show for turning off at a junction (presumably just a green for clear, straight ahead?). I bought the Canadian Trackside Guide - a masterful publication - but I can't say I'm any the wiser for reading it. Can someone sum it up in half a dozen simple sentences?

And while I'm on the subject, I'll be in Canada later this spring. I found a good spot at Toronto Union last year (on the 'balcony' at the end of the Skywalk) but is there somewhere not too far from there that would give me a different viewpoint? Maybe somewhere at the East side of the station, too?

CHRIS LEIGH

[PaulRhB]

I got the Railroad Signalling book by Brian Solomon which gives an idea but isn't that specific due to the wide range from what I remember, I'll have a look if there's anything on Canada.

I've not studied the Canadian ones but is this the same from BNSF to what you've seen? This sites got good step by step illustrations.

http://www.lundsten.dk/us_signaling/abs_apb/index.html

 

[dibber25]

I'm really looking at a multiple track main line where, say, a two track line becomes 4 tracks. The overhead gantry has two or three individual signals above each track. On that single track diagram I can't get my head round the fact that the 'default' aspect seems to be green. It all seems very alien to UK eyes.

CHRIS LEIGH

[The Stationmaster]

Start right at the top with Lundsten as he does explain a number of principles http://www.lundsten.dk/us_signaling/index.html

This might also help although it is really USA based http://www.railway-technical.com/US-sig.shtml

[dave1905]

Try as I might, I can't get my head round the Canadian signalling system. I appreciate it is similar to our Absolute Block System but it's the actual trackside indications that i don't understand - the different colour combinations that seem to mean different things.

 

The N american signals systems are different than European systems.

 

I have a 1929 CN rule book, they seem to be route signals, while the 1962 Uniform Code of Operating Rules were speed signals.

 

Going by the '62 UCOR:

 

A green signal on top and all red below it is clear.

A yellow signal on top and all red below it is Approach. Approach means reduce to medium speed immediately and prepare to stop at the next signal.

All red is stop and proceed, stop, then proceed at restricted speed.

All red with an "A" plate on the mast is Stop.

 

Generally if the signal is for a diverging route the signal will be red on top with a yellow or green below it. The rules will have verbiage talking about some sort of reduced speed through or within interlocking limits or turnouts.

 

There are a lot of other variation that require reduced speed.

 

I am much more familiar with route signalling.

 

For instance, they don't seem to have 'feathers' on their signals so how do you tell if its a junction signal and if you are going to diverge at the next turnout?

 

Feathers are a completely unknown concept in N America. Don't use them, don't need them. Normally junction signals have more than one head on them and display diverging indications (those that require a restricted speed through the interlocking limits or through turnouts.)

 

Is there a sequence of warning signals, and if so, what aspects would they show for turning off at a junction (presumably just a green for clear, straight ahead?). I bought the Canadian Trackside Guide - a masterful publication - but I can't say I'm any the wiser for reading it. Can someone sum it up in half a dozen simple sentences?

 

If the diverging route is signalled and clear the signal at the junction will be (listed top to bottom) medium clear (R-G-R), limited clear (R-G-R with "L" plate) or slow clear (R-R-G). Which one depends on the speed through the interlocking, medium - less than 30 mph, limited - less than 45 mph, slow - less then 15 mph.

The signals before that will be a sequence of approach signals to bring the speed down to the appropriate speed at the junction, for example an approach medium (Y-G-R) or approach limited (Y-G-R with "L" plate) or approach slow (Y-Y-R).

[BR60103]

Chris:

as far as I can tell, it's up to the signalman to set the route correctly and the engineer to adjust his speed to it.

I recall one (and only one) time where the train I was on took off on the wrong line at a junction. It actually had to proceed a bit farther down the line so that the signals could be cleared and we could back down and get on the right line.

The only route signals I figured out were for the scissors crossovers on the Toronto subway.

 

And we don't get those massive gantries with hundreds of signals like Crewe or Derby.

 

There is one signal for each track (maybe fewer if some tracks only have traffic in the other direction). More heads just mean more complicated directions -- speed through the interlocking + speed to the next signal + the next signal may be at caution or danger Clear to Stop or Stop and Proceed.

[BR60103]

Also, all the heads on a signal must be lit. If one of them is dark, the signal must be read as its most restricting interpretation. That's usually (I think always) taking the dark head as red.

[dibber25]

Thanks. I think I'm beginning to get my head around it.

CHRIS LEIGH

[trisonic]

I'm glad you are, Chris!

I've got a headache.....it makes quantum physics look easy.

 

Best, Pete.

[Supaned]

Chris ,

 

If you haven't already got a copy, "Canadian trackside Guide" published by Bytown Railway Society may be of use . As well as comprehensive fleet lists , it also contains sections on things such as signalling , horn codes , and also has radio frequencies and route guides. I know that Ian Allen bookshops stock them as the one in Birmingham has them in stock.

 

HTH

[dave1905]

as far as I can tell, it's up to the signalman to set the route correctly and the engineer to adjust his speed to it.

 

You also have to understand there are different types of signal systems in the US, automatic block signal (ABS) where the switches are manually controlled by the train crews and the signals convey information on speed and track occupancy , but not authority, centralized traffic control (CTC) where the switches and certain switches are manually controlled by the dispatcher or control operator (and the rest are automatic) and interlcokings where the switches and signals at one particular location are controlled manually.

 

The concept of the "signalman" and "signal boxes" was pretty rare over here. Most of the CTC was controlled by an operator or dispatcher that handled from tens to hundreds of miles of territory.

 

So when you ask about signals you sorta have to specify what type of system you are asking about. The signal indications and even signal placement will be different between ABS and CTC.

 

Normally the signals are set up to step the train down in speed in incerments of 15-20 mph to get it to the speed required to pass through turnouts or to slow it to a point where it can get stopped prior to a stop signal.

 

The classic system would display clear then approach then stop.

If the indications talk about a reduced speed through an interlocking or turnouts, they are signals that used for diverging moves or at junctions.

Signals that involve reductions in speed and don't talk about interlockings or turnouts are used to reduce the speed of the train in advance of an interlocking or stop signal.

A signal displaying a restricting signal commonly indicates movement into a non-signalled track other than a main track (yard, siding, interchange, etc).

The higher the speed of the track, the more advance signals will be used. If the top main track speed is 50 mph, they won't be using "limited" indications because that slows the trains down to 45 mph and the next step down is medium speed, 30 mph. On the other hand if the speed on the track is 70 or 80 mph then they will step the train down using limited, then medium speeds. Not all indications are used in all locations.

 

The only route signals I figured out were for the scissors crossovers on the Toronto subway.

 

Subway systems often used different signal systems from regular railroads, so they can be a special case.

 

There is one signal for each track (maybe fewer if some tracks only have traffic in the other direction). More heads just mean more complicated directions -- speed through the interlocking + speed to the next signal + the next signal may be at caution or danger Clear to Stop or Stop and Proceed.

 

One signal that seems to confuse the heck out of people across the pond is the stop and proceed signal. it is a completely different signal than stop. It is used in different situations and has different rules governing it. Many roads in the US have now renamed the stop and proceed signal to "restricting". Its purpose is to get the train down to restricted speed because there is something ahead of it that is either an obstruction (cars, trains, switches open, broken rail) or not signaled (siding, yard, etc). Although it may require a train to stop, its purpose isn't to stop the train. Its intent is to keep the train moving. We don't use the term "danger" signal, except maybe in the case of flagging, when there is, well, danger. We don't consider a stop signal, which happens hundreds of thousands of times a day, to be particularly dangerous. Actually a stop signal is often considered the safest signal, the old saw is "a stopped train is a safe train."

 

The other thing to realize is that in N America, the railroads are private companies and own their own track so are free to install their own signal systems and create their own rules to operate their own trains. They all used a similar template, but that's why there are variations. As railroads merged they inherited different signal systems and it takes time to consolidate them. When the UP merged with the SP, the UP had to put semaphore signals back into its rules because the SP still had a couple subs with semaphores. They were replaced and a few years later the UP got rid of semaphores. The NS is in the process of replacing the PRR position lights with modern color signals.

[dave1905]

Also, all the heads on a signal must be lit. If one of them is dark, the signal must be read as its most restricting interpretation. That's usually (I think always) taking the dark head as red.

 

Generally correct. If a signal that is normally lit is dark. There are some aspects that involve dark signals. Technically its not that you take the signal as red, the signal becomes the most restrictive it can display, which is either stop or stop and proceed.

[dibber25]

Back in 2006, on a trip out of Vancouver with the 2816, I recall watching a bunch of Brits on the train - all railway enthusiasts of the 'old school' - trying to figure out what the different indications meant. They were trying to apply the 'one signal aspect/one track/one train principle and couldn't get their heads round the different combinations of colours. I didn't even try! I'll admit that I've been trying to figure out how those three guys who died at Burlington recently might have mis-read a signal.

CHRIS LEIGH

[dave1905]

A lot of people who find signals confusing think the reason crews don't comply with signals is they are confused also. Not so. Most of the time the crews either don't see the signals (asleep or doing something else), have it in their mind that the signal "should" be one thing and don't really read the signal, assume that the signal will be one indication or that one situation is happening and its really another.

Its amazing how many times a crew can look at a signal (approach) and see something different (clear).

 

For somebody for N America the UK system seems terriblly complicated with signals all over the place and those feather thingys.

 

The signals govern the movement of the track they are over or next to. Really all the engineer needs to know is how fast to go and what to do at the next signal. The specific route is irrelevant. If its CTC or an interlocking he can't control the route, the dispatcher or control operator does. Unless the train is traveling on an approach or diverging approach/approach medium or on an indication requiring restricted speed, they aren't going to be able to get stopped before passing the signal and entering the route anyway.

[BR60103]

Chris: your other question.

There's no bridge over the tracks east of Toronto Union. If you go down to the Don River the Expressway crosses over but that's (a) no place to walk and ( B) no place ypu'd want to stop your car. (just checked Goggle; this road goes under).

Also most of the space along the tracks is filled with high private buildings so you can't even go in for a side view.

The west end is more interesting becasue the trackwaork is more complicated and all trains have to go through there because the yards are much farther west. There are street bridges at Spadina and Bathurst.

 

If you pick the right weekend you can get a walking tour through the station itself, usually including a hike through one of the windows at the end.

[dibber25]

Once again, many thanks for all the help. I find the major difference between the UK and Canadian signalling systems revolves around one word. "Interpretation". There is no interpretation involved in UK signals - red means stop. End of story. I've been looking at the Canadian Trackside Guide and I see there are even instances where the same combination of colours in the same order can have two different meanings (red over green over green = either limited to limited or limited to medium). I accept that there might not be much difference between limited speed and medium speed but the idea that a signal is open to judgement in that sort of fashion just seems wholly alien. Having now read one or two of the TSB accident reports it does seem that signal interpretation routinely comes into play - hence the desire to have voice recording in the cabs. That's only going to tell you what the crew did, and perhaps why. It's not going to prevent it happening again. That has to come from removing ambiguity - and complexity - from the system, surely.

[The Stationmaster]

Once again, many thanks for all the help. I find the major difference between the UK and Canadian signalling systems revolves around one word. "Interpretation". There is no interpretation involved in UK signals - red means stop. End of story. I've been looking at the Canadian Trackside Guide and I see there are even instances where the same combination of colours in the same order can have two different meanings (red over green over green = either limited to limited or limited to medium). I accept that there might not be much difference between limited speed and medium speed but the idea that a signal is open to judgement in that sort of fashion just seems wholly alien. Having now read one or two of the TSB accident reports it does seem that signal interpretation routinely comes into play - hence the desire to have voice recording in the cabs. That's only going to tell you what the crew did, and perhaps why. It's not going to prevent it happening again. That has to come from removing ambiguity - and complexity - from the system, surely.

I've never been keen on any sort of trackside railway signal that can be interpreted in more than one way, whatever railway is using it, but unfortunately the history of British signalling has included such things as well although they have been entirely (speaking from memory) in low speed situations - which are usually the most dangerous of the lot For example the highly rated GWR spent a good decade or more, off & on, debating the meaning of one of its own, fairly common, signals - and still erecting more of them while it did so.

 

But running signal aspects are a different thing and they should have a clear and consistent meaning whether they are in a British based route signalling situation or situation based on speed signalling - the French and Germans have managed to get the latter wholly consistent so it can be done and an intensively worked railway can cope with it.

 

Incidentally as an aside on Chris's original question I recall seeing some years ago something one of my former bosses had obtained on a trip to the USA - issued by Amtrak it was a fold out encapsulated full colour guide to the meaning of signal aspects on every railroad they operated over, it amounted to equalling 6 sides of A4 paper!

[dave1905]

Once again, many thanks for all the help. I find the major difference between the UK and Canadian signalling systems revolves around one word. "Interpretation". There is no interpretation involved in UK signals - red means stop. End of story. I've been looking at the Canadian Trackside Guide and I see there are even instances where the same combination of colours in the same order can have two different meanings (red over green over green = either limited to limited or limited to medium).

 

Be careful using a railfan guide to ascertain signals, they probably have combined signals from multiple companies into one book. If you actually read a rule book or special instructions for a specific railroad you will find that one combination of colors has one meaning. Same with the Amtrak guide, the Amtrak guide would have to be a summary of every signal system in the entire US. Obviously no crew travels the entire US, and no crew would have to know all those signal aspects and indications. At any given spot only a subset of those aspects or indications would be used.

 

For example on the UP in 2005 (the special instructions I have handy) there are 22 signal rules, but 95% of all the crews on the railroad will only see 11 of those signals. The rest are special case signals only used in limited areas, for example 3 are only used at on interlocking at the Metra commuter train station in Chicago and 4 were only used on the former SP Phoenix Sub, a low volume branch.

 

In the current UP rule book they eliminated the 4 signals on the Phoenix Sub (they closed the sub) and combined restricting and stop and proceed as restricting (eliminating stop and proceed).

[pcc4199]

 

Consider the west end of the platforms, as the above link shows.

 

Cheers.

 

Andy

[Fay Singpoint]

I've managed to dig out my photographs of my trip on the Canadian about 5 years which is the 3 times a week service from Toronto to Vancouver. The journey time is 4 days and 3 nights and is a wonderful way to see the country.

 

 

 

The pictures have been taken not long after the train had left Jasper and continued its steady climb over the southern section of the Rockies. The first picture shows our signal showing clear under Rule 405. The quality is not brilliant and is more down to the state of the windows in the observation dome car.

[dave1905]

A passenger in the dome car flags down the conductor and tells him, "We must have a really good engineer, he just makes every green light!"

[jostein]

(...) I find the major difference between the UK and Canadian signalling systems revolves around one word. "Interpretation". There is no interpretation involved in UK signals - red means stop. End of story. I've been looking at the Canadian Trackside Guide and I see there are even instances where the same combination of colours in the same order can have two different meanings (red over green over green = either limited to limited or limited to medium). (...)

 

I can only speak for current CN practice, but in my experience working as a locomotive engineer, there is absolutely no room for 'interpretation' of any kind. A signal indication has a single meaning. In the case you mention above, a solid green light means medium speed (30 MPH), and a flashing green light means limited speed (45 MPH). Thus, Red - Solid Green - Solid Green means "Medium to Medium; proceed, medium speed passing signal and through turnouts, approaching next signal at medium speed". Red - Flashing Green - Solid Green means "Limited to Medium; proceed, limited speed passing signal and through turnouts, approaching next signal at medium speed".

 

To complicate matters, signal indications can be modified by signs attached to the signal mast, so for instance a triangular yellow sign displaying an 'L' attached to the signal mast turns any 'medium' indication into 'limited'. Thus, Red - Solid Green - Red, with an 'L' plate, means "Limited to clear; proceed, limited speed passing signal and through turnouts." Without the 'L' plate, it would be "Medium to clear, etc."

 

I'll be happy to answer any questions about signalling or operating rules, to the best of my ability. As mentioned, I can only speak to current day CN practice. Rules may be different for other NA railroads.

[dave1905]

Exactamundo.

 

One railroad, one aspect, one indication.

[BR60103]

Canada does have the Uniform Code of Operating Rules which apply to most of the companies operating here. My 1962 version lists, in addition to CP and CN, Algoma Central, C&O, Essex Terminal, Napierville Junction, NYC, and 5 more.

The Trackside Guide also seems to indicate that they are for all of Canada. There is a warning that the US may differ.

Chris: there's no note in the 2009 Guide I'm looking at, but a light with little rays coming from it means flashing. RGG has 4 meanings depending on which green(s) is flashing.

 

The 1962 book has only 1 rule with a flashing light in it. Most of the diagrams still show semaphores.

 

There are 3 rules that have all red signals.

428 is Stop and proceed.

429 has an A on the post. This is an absolute Stop.

426 has an R on the post. This is Proceed at Restristed Speed. (will allow stopping within half the range of vision).

 

When looking at the diagrams, lightsl shown on opposite sides of the post are block signals, sort of a home and distant pair. Lights on the same side of the post are interlocking signals. All red on an interlocking signal is stop. All red on a block signal (with no letter) is stop and proceed.

 

Somewhere on the rmweb I posted the pages from the 1962 rule book.

[dave1905]

Just for the record there is no "absolute stop" signal in prototype rules, there are absolute signals and there are stop signals, but there are no rules for "absolute stop signals". Most of the time when somebody talks about an "absolute stop signal" they are talking about a stop signal in CTC or a manual interlocking, a signal where you have to get verbal permission from the dispatcher or control operator to pass, but as far as the signals go a stop signal is the same in ABS, CTC, or an interlocking (manual or automatic).