Jump to content

General Subway/RT Discussion


FlyerD901

Recommended Posts

13 minutes ago, Turtle said:

I should edit my cab signalling comment on line 1...yes they use a form of cab signalling, but they also have to obey the ATC wayside signals. Flashing green means good to go, solid red means stop. So with a red ATC signal in the station, the train can't stop in the proper position. Not too much of an issue with ~452' trains except for passenger comfort and stopping efficiency, but definitely an issue with ~500' trains, since much of the trailing car would be outside of the station on a red ATC signal in some stations, usually those with switches at the leaving end.

But you admit that the wayside is not safety-critical (though it can have safety implications), so a simple rule book change would resolve the issue with a 500ft train.

 

the only issue I could see is with position of the trackside train detection at reverse points (which are used to determine train length), which could affect blocking times leaving terminals.

Link to comment
Share on other sites

29 minutes ago, TTC103 said:

Again, the wayside signals are not safety critical unless your train cannot receive a movement authority from the signaling system. The TTC could rip them out tomorrow with no safety impacts to regular service. They also decrease driver awareness as to which system (CBTC or Auto Train Stop) is working, which resulted in a near-miss two years ago.

Sure they could rip out the ATC wayside signals if they wanted to without any impact to regular properly functioning service in an ATC mode. It changes procedures for non equipped operation, or disabled ATC equipment they are trying to move out of the way of regular properly functioning revenue equipment. There are no train stops (trip arms) in the ATC system, the north end operator mistakenly thought they saw the trip arm go down, when it was tied down. They thought they had a favorable signal to leave the pocket, they didn't. They were looking at the platform entering light instead of the signal in the pocket (which was red) because the operator couldn't see the signal; it was in their blind spot since the other operator didn't stop in the pocket in the proper position.

 

Now if the ATC system in the pocket had been fully or properly implemented in there at that time, they wouldn't have been allowed to be in an emergency mode, and the train wouldn't have been able to move.

7 minutes ago, TTC103 said:

But you admit that the wayside is not safety-critical (though it can have safety implications), so a simple rule book change would resolve the issue with a 500ft train.

You would have to modify the system to allow a 500' train to be spotted on the platform properly. There are a few situations where this will never be the case in the current version of the system, but not as big a deal as the platform gap issue.

Link to comment
Share on other sites

I do agree that the TTC relies too much on degraded mode working in regular operations. I understand why RM was needed for the SB move, but there was no reason for the train to be in RM on the NB move.

 

In a system without wayside signals, that move would have had to be done under the direction of the signaler. The fact that the NB driver had to look for a wayside signal opened up the possibility that Auto Train Stop was active, so the decision to use wayside signals did cause the incident.

Link to comment
Share on other sites

3 minutes ago, TTC103 said:

I do agree that the TTC relies too much on degraded mode working in regular operations. I understand why RM was needed for the SB move, but there was no reason for the train to be in RM on the NB move.

 

In a system without wayside signals, that move would have had to be done under the direction of the signaler. The fact that the NB driver had to look for a wayside signal opened up the possibility that Auto Train Stop was active, which caused the incident.

The train wasn't in RM mode, they don't use RM mode for anything. It had a purpose that some engineer thought would be useful but in practice it never gets used. It's a different emergency mode they used, but you're correct in saying that an emergency mode shouldn't have been necessary to move a train out of the pocket, but back then it was common practice for other center tracks and pockets to use an emergency mode to drive the train out.

Link to comment
Share on other sites

21 minutes ago, Turtle said:

You would have to modify the system to allow a 500' train to be spotted on the platform properly. There are a few situations where this will never be the case in the current version of the system, but not as big a deal as the platform gap issue.

Are you referring to the portion of the CBTC system that verifies that the train is properly berthed?

Link to comment
Share on other sites

11 minutes ago, TTC103 said:

Are you referring to the portion of the CBTC system that verifies that the train is properly berthed?

Don't really know what system I am referring to, all I know is a train cannot position itself properly in a station if there is a red wayside signal in the far end of the station, you'll see this if you are a passenger on a train coming to an unusual stop, usually slow down, accelerate a little slow down some more, accelerate a little, slow down to an absolute crawl, accelerate a little ... eventually stop far short of being properly spotted. Northbound St George comes to mind, but there is one in the new section of the line too, can't recall where now. Really frustrating as a passenger when you are in a hurry to get off.

 

Why the signal is red is irrelevant, it should be favorable to allow the train to spot properly. Most likely the train is going to be held for headway adjustment or something like that, so it isn't a safety issue with the switch ahead or distance from another train.

 

Another thought came to mind with 500' trains (Osgoode pocket specifically) is fitting them in pockets or center tracks. That's another issue they should verify before going through the expense of buying extra (shorter) cars to make a 500' train.

Link to comment
Share on other sites

Just continuing on about my "line 1 ATC trains don't use cab signalling" comment to explain my thinking a little better:

 

The information on the operator display in the train is limited, and forces the operator to make educated guesses about switch position. The wayside ATC signals in equipped atc modes also give limited information, only proceed or stop. No directional information. They are nice to have, but as TTC103 insists are not needed in normal circumstances.

 

The old legacy system gave a ton of information on wayside signs and signals. Speed, direction, ability to pass, what is up ahead at the next wayside signal, and so on. The ATC "cab signals"? Only basically how fast you can go, or if you can go at all from a stop, and error messages. Lots of in service trains have ended up in Wilson Yard with passengers onboard because the system (or the person running the system) mistook the train for a run in train. Back with the legacy system, that was a huge deal for the operator to take wrong routing, but now when the system does it, not a big deal just wait a second while we get you routing out. A driver with experience and who is paying attention can pick up on this before it happens from the clues the train gives, but there is nothing that tells the driver that the train is going to take an alternate route in an ATC mode other than the bug speed dropping to 30km/h in a section that is usually above 50km/h with the yard nearby.

 

That is where my "they don't use cab signalling on line 1" argument came from. If you want to insist they do use cab signalling. I will then point out that line 2 uses a form of cab signalling also when the speed control system is properly working.

Link to comment
Share on other sites

5 hours ago, Turtle said:

Just continuing on about my "line 1 ATC trains don't use cab signalling" comment to explain my thinking a little better:

 

The information on the operator display in the train is limited, and forces the operator to make educated guesses about switch position. The wayside ATC signals in equipped atc modes also give limited information, only proceed or stop. No directional information. They are nice to have, but as TTC103 insists are not needed in normal circumstances.

 

The old legacy system gave a ton of information on wayside signs and signals. Speed, direction, ability to pass, what is up ahead at the next wayside signal, and so on. The ATC "cab signals"? Only basically how fast you can go, or if you can go at all from a stop, and error messages. Lots of in service trains have ended up in Wilson Yard with passengers onboard because the system (or the person running the system) mistook the train for a run in train. Back with the legacy system, that was a huge deal for the operator to take wrong routing, but now when the system does it, not a big deal just wait a second while we get you routing out. A driver with experience and who is paying attention can pick up on this before it happens from the clues the train gives, but there is nothing that tells the driver that the train is going to take an alternate route in an ATC mode other than the bug speed dropping to 30km/h in a section that is usually above 50km/h with the yard nearby.

 

That is where my "they don't use cab signalling on line 1" argument came from. If you want to insist they do use cab signalling. I will then point out that line 2 uses a form of cab signalling also when the speed control system is properly working.

The CBTC system does communicate the route to the vehicle: the 'communications' consist of route info (civil speed limits, grades, and any temporary speed restrictions) and the vehicle's End of Authority). This info is used by the train to compute a brake curve, which is the ATP system supervises, intervening if there is a violation. The train in turn communicates the position of its front end, speed and integrity information to the system, which is used to detect the train (for the purpose of generating movement authorities and setting/cancelling routes at interlockings)

It's honestly shocking how poorly the TTC trains its staff on safety. The trains speed dropping to 30km/h is not a 'bug', but happens because the route information (which includes speed limits) is communicated to the train, and is used to calculate the braking curve. Your comment about 'an experienced operator who is paying attention' suggests that management does not teach it's staff how the safety-critical protection system works, and staff are instead learning while in revenue service.

Link to comment
Share on other sites

18 hours ago, 81-717 said:

I meant "articulated" in the general sense, the way the general public considers the TRs to be articulated, but I definitely see your point about each car being able to ride the rails independently. Indeed, anything that doesn't meet that criterion is not technically a "car", but rather a "section". i.e. a Flexity doesn't consist of 5 cars permanently linked together, but rather a single car made up of 5 articulated sections. If the TRs had the trucks mounted directly under the open gangways, they would be more accurately described as a single long car made up of 6 sections, rather than a 6-car train. Same with intermodal freight cars consisting of 3–5 sections (even though it's possible to add/remove those sections as needed). The C20 in Stockholm has a particularly unusual configuration for a subway, since each set consists of 3 sections, with the middle section/car having 2 trucks like a normal car, and the cab sections having only 1 truck at the cab end, with the other end being supported by the middle car.

There is no "general sense" - articulated means a pretty well-defined thing in vehicles.

 

You can continue to call the TRs articulated, but you will still be wrong.

 

18 hours ago, 81-717 said:

Do the diaphragms used on GO trains need to be connected together beyond just coupling the cars together, since they're of a different design than the tubular diaphragms used on, for example, Long Island & Metro-North?

 

No.

 

All railroad diaphragms are designed to work and interface with each other in the same manner, regardless of their design and manufacture. There are no physical interlocks. Excepting things like couplers, a GO car could couple up to an LIRR car and you would be able to walk through them safely.

 

As they are longer than the distance between the end of the car and the pulling face of the coupler, once coupled together the spring mechanism becomes preloaded and prevents gaps from forming between the two.

 

18 hours ago, 81-717 said:

Since it is doable with fully open gangways like on the TR, would it be possible to have half-a-pair of bellows at the end of each car, that would be connected in the middle when the cars are coupled together? Another factor besides curve radius is the wheelbase & overhang (the reason the 75' cars in NYC have locked intercar doors is due to their longer overhang than that of the 60' cars). According to TTC subway car specs, the minimum curve radius they're designed for is 116 m, which is not that much smaller than the 125/175 m minimum preferred radius on mainline rail, but the minimum radius found on the NYC subway is apparently as small as 29 m (probably for the smaller A-division cars only, since I would expect the 75' B-division cars to have a similar minimum curve radius to the Toronto subway cars, which are the same length & probably similar wheelbase).

 

This, I am less sure about.

 

The way that the covered gangways work in most subway cars and LRVs is that it covers the full distance between the carbodies. It then gets bolted to both sides once the cars are assembled into a unit.

 

This way, there is no join in the middle that can slide apart from each other and become mis-aligned or pull apart on really tight curves. The downside is - as the TTC has discovered - that there is now a new wear item that needs to be replaced every X miles.

 

By the way, the minimum radius in Toronto is something like 60m, not 116m. 116m is the new minimum mainline curve radius is, just like the minimum mainline gradient is 3% even though there are locations of 5% and more on the current system.

 

18 hours ago, 81-717 said:

Speaking of the next generation of subway cars, has the order been finalized at this time (or will be in the near future)? There isn't much information out there beyond that it has been moved back into this decade despite still being largely "unfunded", and the expected timeframe of delivery of a prototype & production fleet (of course, we can't expect those timeframes to be met if the project remains unfunded for the next few years).

 

Manufacturers have been canvassed, and information sent to them. Beyond that, I don't know.

 

18 hours ago, 81-717 said:

If they want to be able to easily switch between 4- and 6-car trains, especially if it's easier to maintain 2-car sets at Greenwood, they could always switch back to the married-pair configuration, but with open gangways between each pair (similar to how the brand new M8/9s on MNRR/LIRR have retained the married-pair configuration). Now if they want to add a 7th car, that makes things more complicated, since it would require adding an extra single car, or having longer sets (2+2+3, 4+3 or a 7-car set). Is the plan to have 7 cars of equal length (slightly shorter than 75'), or 6 standard-length cars and a shorter 7th car?

 

The info sent out to manufacturers called for just that - the trainsets being configured as 2-car married pairs of two configurations (an A+B pair, where the A car has a cab and a gangway at one end and a B+C pair, where both cars have gangways at both ends but the C car having hostler controls), with the systems being smart enough to configure everything based on what pairings were coupled. As well, it also called for a single car that could be added to the trainset, and like the others be integrated into the trainset automatically.

 

18 hours ago, Turtle said:

Line 1 isn't cab signaled, they rely on wayside signals much like Line 5 is going to use. A lot less of them, but any interlockings have wayside signals still, and there are a few random signals to control movement otherwise. Grade timing is replaced by the ATC system, but wayside signals still exist.

The wayside signals are solely to guard the interlockings from any non-equipped equipment. They may change as the equipment comes through, as they are also detecting each train as it goes through, but they are not operated on in regular operation.

 

Dan

  • Thanks 1
Link to comment
Share on other sites

2 hours ago, TTC103 said:

The CBTC system does communicate the route to the vehicle: 

Sure it does, but the vehicle doesn't communicate routing to the operator, the person who is onboard supervising the vehicle to make sure everything is okay. The only way an operator will know for sure if the train is taking alternate routing is when the switch is visible (way too late) or when the train diverges (bad if not supposed to). 

2 hours ago, TTC103 said:

It's honestly shocking how poorly the TTC trains its staff on safety. The trains speed dropping to 30km/h is not a 'bug'

I used the term "bug speed" to indicate the speed at which the train is permitted to go, as shown on the operator display.

 

That display also shows distance to stop (allowed distance to travel, not necessarily to station), and modes. No information is displayed about route, so it is an educated guess to why the train is slowing down. It could either be for a slow order on the tracks ahead, or a divergent route, or a divergent route in a slow order. It's a guess, and it shouldn't be. 

1 hour ago, smallspy said:

 

The wayside signals are solely to guard the interlockings from any non-equipped equipment. They may change as the equipment comes through, as they are also detecting each train as it goes through, but they are not operated on in regular operation.

 

Dan

They are a display for the operators of any train in the system equipped or not to give them information on what is permitted there. Same function as the legacy signals, except enforcement is by electronic systems instead of physical valves and switches. Legacy has the trip arm, ATC has the computers. Unequipped passing a red In an ATC section will not be stopped by anything except the operator (i.e. just like in Osgoode pocket). That's the biggest problem with the system 

Link to comment
Share on other sites

6 hours ago, Turtle said:

They are a display for the operators of any train in the system equipped or not to give them information on what is permitted there. Same function as the legacy signals, except enforcement is by electronic systems instead of physical valves and switches. Legacy has the trip arm, ATC has the computers. Unequipped passing a red In an ATC section will not be stopped by anything except the operator (i.e. just like in Osgoode pocket). That's the biggest problem with the system 

Yes, but....

 

Their actual indication is irrelevant to the operators, as the signal indication system onboard each train also displays the progressions and allowances that the system gives them. Unlike with the older system, a signal could be obscured but the trains could still run through it as the interlocking that it is guarding has already transmitted its permission.

 

The Osgoode Pocket incident had more to do with the ATC being turned off in there than anything else. At that point, there was no protection whatsoever.

 

Dan

Link to comment
Share on other sites

6 minutes ago, smallspy said:

Their actual indication is irrelevant to the operators, as the signal indication system onboard each train also displays the progressions and allowances that the system gives them. Unlike with the older system, a signal could be obscured but the trains could still run through it as the interlocking that it is guarding has already transmitted its permission.

 

Yes, but...

 

How does the operator know which direction the train will go over the switch? Not important at the ends, but very important in a short turn or moving into the yard on a deadhead trip, or staying on the mainline in service when the train is supposed to remain in service. It's an indication the legacy signal system gives, why wouldn't the operator need to know which way the train is going? The ATC wayside signals give that indication when the train is in an emergency mode or it is unequipped for whatever reason, why not have a couple warnings, audible and visual in the cab? Shute, even the Speed Control system did that at first, until they took that feature away. All it would take is a warning tone of some sort, and a flashing arrow on the operator display in the trains.

 

Before ATC they weren't allowed to take passengers on a tour of the yard, but now it seems like it's okay since nobody is in control of the trains anymore.

14 minutes ago, smallspy said:

The Osgoode Pocket incident had more to do with the ATC being turned off in there than anything else. At that point, there was no protection whatsoever.

So you went from claiming it was because a feature was missing or turned off in there to it was turned off completely?

Link to comment
Share on other sites

6 minutes ago, Turtle said:

 

Yes, but...

 

How does the operator know which direction the train will go over the switch? Not important at the ends, but very important in a short turn or moving into the yard on a deadhead trip, or staying on the mainline in service when the train is supposed to remain in service. It's an indication the legacy signal system gives, why wouldn't the operator need to know which way the train is going? The ATC wayside signals give that indication when the train is in an emergency mode or it is unequipped for whatever reason, why not have a couple warnings, audible and visual in the cab? Shute, even the Speed Control system did that at first, until they took that feature away. All it would take is a warning tone of some sort, and a flashing arrow on the operator display in the trains.

 

Before ATC they weren't allowed to take passengers on a tour of the yard, but now it seems like it's okay since nobody is in control of the trains anymore.

The TTC should not have accepted an Auto Route Setting system that regularly misroutes trains. Other agencies wouldn’t tolerate this from a vendor. Or maybe the TTC isn’t properly assigning train IDs.

Do the misroutes into the yard occur to trains following on runs into the yard/storage track (as intended). If that’s the case, the ATS system isn’t properly spacing trains, causing the switch to lock to the wrong route. If not, it’s probably the TTC failing to update train IDs when performing real-time rescheduling. In either case, the solution is to fix the underlying cause of the misrouting, not to add wayside signals with route info.

Link to comment
Share on other sites

24 minutes ago, TTC103 said:

The TTC should not have 

Omfg, how about just giving complete information in an intuitive form to the person who is ultimately responsible for the safe operation of the train without having to guess at what is about to happen? It's pretty simple 

Link to comment
Share on other sites

13 hours ago, smallspy said:

There is no "general sense" - articulated means a pretty well-defined thing in vehicles.

You can continue to call the TRs articulated, but you will still be wrong.

Well, I had no idea the term had been widely misused/misunderstood in its popular usage. When the TRs first came out there was certainly a lot of hype about them being the first "articulated" subways in North America.

13 hours ago, smallspy said:

Excepting things like couplers, a GO car could couple up to an LIRR car and you would be able to walk through them safely.

I had no idea that LIRR/MNRR electric railcars didn't use the standard railroad coupler design, until I looked at some photos & realized they instead use a design similar to that used in the subway. I assumed most if not all mainline equipment on the North American rail network would use the same coupler design for convenience.

13 hours ago, smallspy said:

By the way, the minimum radius in Toronto is something like 60m, not 116m. 116m is the new minimum mainline curve radius is, just like the minimum mainline gradient is 3% even though there are locations of 5% and more on the current system.

I was going by the specs listed for the T1s. Which sections of Toronto's subway network have 60m curves, and which mainline sections have 5% grades?

13 hours ago, smallspy said:

The info sent out to manufacturers called for just that - the trainsets being configured as 2-car married pairs of two configurations (an A+B pair, where the A car has a cab and a gangway at one end and a B+C pair, where both cars have gangways at both ends but the C car having hostler controls), with the systems being smart enough to configure everything based on what pairings were coupled. As well, it also called for a single car that could be added to the trainset, and like the others be integrated into the trainset automatically.

That's a rather unusual configuration (normally a married pair has 1 cab per car, and a longer fixed set has a cab in the 1st & last car), I guess the closest analog would be Washington's 7000 series. To the average passenger, a 6-car train in (A-B)+(B-C)+(B-A) configuration would be basically indistinguishable from the TR configuration.

Link to comment
Share on other sites

13 hours ago, Turtle said:

Omfg, how about just giving complete information in an intuitive form to the person who is ultimately responsible for the safe operation of the train without having to guess at what is about to happen? It's pretty simple 

My point was that the TTC accepted the Automatic Train Supervision (ATS) system from Alstom in its current state, where it occasionally misroutes trains, giving rise to the issues you mention. The system is supposed to be capable of GoA4, where there is no driver to notice if the train is being misrouted.

The solution you propose (giving the driver route information), while eliminating the issue of passengers being carried into the yard, does not fixed the core issue (that the ATS system cannot reliably identify the route the train needs), and results in less reliable service. Every time a train is incorrectly routed, the driver has to stop the train, and call the signaller to get the proper route set before proceeding. While route cancelling is faster with CBTC compared to Automatic Train Stop, this action results in less reliable travel times, which reduces Line 1's realizable capacity.

Given the importance of Line 1 to the TTC, and the need for increased capacity, it is critical that the ATS system function properly. Then again, the TTC is a notoriously difficult customer, and management has a history of ignoring vendors' advice.

Link to comment
Share on other sites

15 hours ago, Turtle said:

Yes, but...

 

How does the operator know which direction the train will go over the switch? Not important at the ends, but very important in a short turn or moving into the yard on a deadhead trip, or staying on the mainline in service when the train is supposed to remain in service. It's an indication the legacy signal system gives, why wouldn't the operator need to know which way the train is going? The ATC wayside signals give that indication when the train is in an emergency mode or it is unequipped for whatever reason, why not have a couple warnings, audible and visual in the cab? Shute, even the Speed Control system did that at first, until they took that feature away. All it would take is a warning tone of some sort, and a flashing arrow on the operator display in the trains.

 

In theory, the system onboard will tell them.

 

The reality is that there are many times where the operator won't be able to discern what the routing may end up being because of other traffic ahead. But by that same token, there are places on the legacy system where the operator may get routed into a pocket track for a short-turn and not know about it a station before - and it's happened in the past with passengers onboard. The signal system shouldn't be a replacement for good communication between wayside and the trains.

 

15 hours ago, Turtle said:

Before ATC they weren't allowed to take passengers on a tour of the yard, but now it seems like it's okay since nobody is in control of the trains anymore.

 

Just because it wasn't allowed doesn't mean that it didn't happen.

 

15 hours ago, Turtle said:

So you went from claiming it was because a feature was missing or turned off in there to it was turned off completely?

 

You're trying to equate spur-of-the-moment speculation to actually reading the results of the findings? Nice.

 

1 hour ago, TTC103 said:

My point was that the TTC accepted the Automatic Train Supervision (ATS) system from Alstom in its current state, where it occasionally misroutes trains, giving rise to the issues you mention. The system is supposed to be capable of GoA4, where there is no driver to notice if the train is being misrouted.

It doesn't "occasionally misroute" trains.

 

The system does exactly what the people in control tell it to do. If someone misroutes a train in control, that's on them, not the system.

 

9 hours ago, 81-717 said:

Well, I had no idea the term had been widely misused/misunderstood in its popular usage. When the TRs first came out there was certainly a lot of hype about them being the first "articulated" subways in North America.

 

But even if you mis-use the word "articulated", they weren't even close to the first in North America. New York and Chicago both have them beat, and so does Boston if you count the Green Line.

 

9 hours ago, 81-717 said:

I had no idea that LIRR/MNRR electric railcars didn't use the standard railroad coupler design, until I looked at some photos & realized they instead use a design similar to that used in the subway. I assumed most if not all mainline equipment on the North American rail network would use the same coupler design for convenience.

 

It's dependent. Freight equipment by rule needs to use a standardized coupler design and location, along with a standardized brake hose and fitting.

 

But for passenger equipment, I'm not sure that there is a similar rule. While the MR90s used standard knuckle couplers at both ends, most of the modern (and even older) US MU equipment use automatic couplers to allow for rapid lengthening and shortening of the trainsets.

 

9 hours ago, 81-717 said:

I was going by the specs listed for the T1s. Which sections of Toronto's subway network have 60m curves, and which mainline sections have 5% grades?

 

The loop at the bottom of Greenwood is give-or-take 60m radius, and the old loop at Wilson was something similar.

 

Sections of the original Yonge Line are 5%. I think that the grades into York Mills are not quite as steep but not far off, either. The grade north out of Dupont is also quite steep.

 

9 hours ago, 81-717 said:

That's a rather unusual configuration (normally a married pair has 1 cab per car, and a longer fixed set has a cab in the 1st & last car), I guess the closest analog would be Washington's 7000 series. To the average passenger, a 6-car train in (A-B)+(B-C)+(B-A) configuration would be basically indistinguishable from the TR configuration.

That's the hope. And it would easily allow the TTC to build 4-car trainsets for Sheppard if/when that line gets extended (assuming, of course, that it gets extended while this hypothetical new fleet is still around).

 

Dan

  • Like 1
Link to comment
Share on other sites

1 hour ago, smallspy said:

It doesn't "occasionally misroute" trains.

The system does exactly what the people in control tell it to do. If someone misroutes a train in control, that's on them, not the system.

Route setting is automatic, based on the train ID (which identifies the path). There is no human involvement in route setting outside of degraded operations scenarios.

There are documented cases of ATS systems misrouting trains in other migrations. On the migration of the Hong Kong East Rail Line to CBTC (by Siemens), there were issues where late communication of a switch being released (from ATP to ATS) resulted in the ATS not having enough time to safely request the new route. I am not sure if that is the case here, but the solution is to ensure that trains are properly identified by the ATS, and that the system is provisioning enough time to safely set up a new route.

 

1 hour ago, smallspy said:

In theory, the system onboard will tell them.

 

The reality is that there are many times where the operator won't be able to discern what the routing may end up being because of other traffic ahead. But by that same token, there are places on the legacy system where the operator may get routed into a pocket track for a short-turn and not know about it a station before - and it's happened in the past with passengers onboard. The signal system shouldn't be a replacement for good communication between wayside and the trains.

The Alstom Urbalis ATP system is a cab signaling system with continuous transmission between train and signaling system, so there is no need for any wayside equipment other than track-clear detection at interlocking locations and to measure the train's length after cab set up. Adding wayside route signaling increases costs with zero benefit to operations. It also reduces driver awareness as to which mode they are operating in, which was one of the causes of the Osgoode near-miss. Replacing the signals with TVM or ETCS boards to mark EoA locations is cheaper and safer.

Link to comment
Share on other sites

9 hours ago, TTC103 said:

Route setting is automatic, based on the train ID (which identifies the path). There is no human involvement in route setting outside of degraded operations scenarios.

Yes and no.

 

Yes, the system allows it, and yes, the TTC has implemented it.

 

But no in the sense that it gets overridden by the humans at the control center frequently for any number of different reasons.

 

9 hours ago, TTC103 said:

There are documented cases of ATS systems misrouting trains in other migrations. On the migration of the Hong Kong East Rail Line to CBTC (by Siemens), there were issues where late communication of a switch being released (from ATP to ATS) resulted in the ATS not having enough time to safely request the new route. I am not sure if that is the case here, but the solution is to ensure that trains are properly identified by the ATS, and that the system is provisioning enough time to safely set up a new route.

 

You may want to read about the other issues that arose from that particular installation. While at first blush it may seem like there are parallels, the reality is that the install in Toronto has been far, far more systematic and structured.

 

9 hours ago, TTC103 said:

The Alstom Urbalis ATP system is a cab signaling system with continuous transmission between train and signaling system, so there is no need for any wayside equipment other than track-clear detection at interlocking locations and to measure the train's length after cab set up. Adding wayside route signaling increases costs with zero benefit to operations. It also reduces driver awareness as to which mode they are operating in, which was one of the causes of the Osgoode near-miss. Replacing the signals with TVM or ETCS boards to mark EoA locations is cheaper and safer.

 

Thanks for being able to read and regurgitate marketing wank.

 

The reality is that there will always be a need for wayside-to-onboard communications, and so long as there are people the cab those communications need to go to them.

 

 

8 hours ago, Turtle said:

In practice it doesn't

 

So, you chose to selectively ignore the rest of my comment then, eh?

 

Dan

Link to comment
Share on other sites

8 hours ago, smallspy said:

So, you chose to selectively ignore the rest of my comment then, eh?

I skimmed it, agree with some of it, had nothing to add since all I'm doing is repeating the same thought. I've made my point, that the routing information on the "cab signalling" displays would be a nice to have thing for the operator who cares about preventing stupid delays. In the past with the legacy system, if an operator took a train full of people on an alternate route that isn't part of regular service or otherwise authorized in advance, say into a center/pocket track or in the yard with people onboard for example, that would result in serious discipline for the operator. Probably a drug test too.

 

But now, no consequences since the operator is simply there to respond after the fact when something happens.

 

With the legacy system, the operator knows well in advance where the train is going to go, and has plenty of time to react to it. With ATC, like I said previously before you wrote the paragraph that I hadn't responded to in that previous post, you stated there is enough information on the operator display in the cab for an operator to make a pretty reliable guess at where the train is going to go.

 

But this system would be capable of running the trains completely operatorless, so this discussion is pointless

Link to comment
Share on other sites

Just to illustrate, with the legacy system, with alternate routing into the yard or a center track, typically you would have:

-a flashing grade timing wayside sign or multiple flashing grade timing signs or illuminated flashing off markers in the case of York Mills Center track, or an illuminated grade timing sign showing lower grade timing, inconsistent throughout the system

-a reduction in speed enforced by "slower" grade timing in that section

-warnings on the speed control cab signalling equipment to indicate the reduction in speed and sometimes a warning about alternate routing

-an indication on the last wayside signal before the switch that it is giving alternate routing

 

With ATC you get:

-a reduction in the authorized speed, displayed on the display in the cab

-a flashing green on the ATC wayside signal closest to the switch with alternate routing

***this also occurs for a train being driven manually by the operator in fully equipped ATC mode. This is regular operating practice, and does not need to be authorized by anybody. This is the mode the line 5 lrt trains will use in the outdoor sections, or when there is some irregularity in the track ahead like an active work zone

Link to comment
Share on other sites

 

10 hours ago, smallspy said:

You may want to read about the other issues that arose from that particular installation. While at first blush it may seem like there are parallels, the reality is that the install in Toronto has been far, far more systematic and structured.

You realize the TTC ordered Alstom to design the Osgoode Interlocking without proper flank protection, which resulting in a near-fatal incident? The proper route set up involves occupying the section of track between the equilateral switch in the pocket and the trailing switch, so that fouling results in the MA being revoked. A systematic and structured migration would have been one where TTC listened to the signalling engineers at Alstom that told them the route set up was not safe.

 

10 hours ago, smallspy said:

Thanks for being able to read and regurgitate marketing wank.

 

The reality is that there will always be a need for wayside-to-onboard communications, and so long as there are people the cab those communications need to go to them.

The reality is that nearly every installation of Alstom CBTC does not have wayside signals, as all safety-critical information is communicated from radio to train. Some of these were GoA2 Applications, like the migration of the Amsterdam Metro, and GoA4 applications in Lille, Lausanne, Hong Kong and Singapore. These systems work using a traffic management system which contains the paths for each train and their order at interlocking locations, with is used to set and release routes, and are designed to function without any external input, obviating the need for the switch position to be communicated to the driver. This isn't marketing wank: it's how the system is designed to work.

I recognize that migrating to a signalling system that doesn't show the route is large change for drivers on the broad gauge lines, but this is how the system is designed to work, and is how signalling works in all of Continental Europe. I understand that this is not something they are used to, but it does not mean that the system is defective. Instead of blaming Alstom for not providing something they don't offer, the TTC should work with Alstom to develop procedures for rescheduling, rerouting and reordering trains in the event of a disruption to ensure that supervisory staff understand how to properly do this.

 

 

I feel like this issue is a good example of why things cost so much for the TTC. I'm sure that Alstom has proposed changes to how the TTC reschedules trains to ensure that trains are always correctly routed, but the TTC and its workers seem to think they understand the problem better than the Alstom's safety engineers, who almost certainly have dealt with this issue before for clients operating driverless trains. If you constantly ignore the advice of experts, and then turn around and blame them after something goes wrong, they might not want to work for you anymore, or they will start charging extra to offset the cost of working with a difficult customer.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...