News   Nov 28, 2024
 112     0 
News   Nov 27, 2024
 893     4 
News   Nov 27, 2024
 729     1 

TTC: Other Items (catch all)

If ATC is active on just a section in the middle, how do they expect tighter separations when the trains entering the section have the traditional wider separation, without feeding trains in and out of the mix? Or am I missing something?
 
If ATC is active on just a section in the middle, how do they expect tighter separations when the trains entering the section have the traditional wider separation, without feeding trains in and out of the mix? Or am I missing something?
It's everything from St. Patrick to Vaughan now isn't it?

Still, your point holds. The answer is they don't. They are just trying to hold the existing schedule. They can't start tightening the scheduled spacing until after they finish the entire line (unless they just want to run some trains on part of the line - but this isn't the section with the higher demand, so they won't.
 
If ATC is active on just a section in the middle, how do they expect tighter separations when the trains entering the section have the traditional wider separation, without feeding trains in and out of the mix? Or am I missing something?

Essentially there is a bottleneck at the conversion point between ATC and block signals. This leads to backups along the line. You have a ton of trains tightly packed from Vaughan to St Patrick but wider headways south. This leads to problems.

They should have done the conversion as a whole before turning the system on but alas they did not.
 
If ATC is active on just a section in the middle, how do they expect tighter separations when the trains entering the section have the traditional wider separation, without feeding trains in and out of the mix? Or am I missing something?
They should have done the conversion as a whole before turning the system on but alas they did not.
There's some serious time-frame issues as to completing the conversion for the whole line:
https://www.theglobeandmail.com/can...ubway-signal-system-upgrade-by-2019-deadline/

Note the spectacular GIFs, one demonstrating the exact 'bunch up' as discussed by posters, even though it isn't marked as such.

My immediate first thought is "CBTC over Moving Block", something quite known and practised, albeit whether the particular software and system the TTC is using can 'overlay' like that is a good question.

Good reading here:
https://www.witpress.com/Secure/elibrary/papers/9781845644949/9781845644949007FU1.pdf

@reaperexpress @Urban Sky and some other posters are right up on this, @KevinT ? As the Globe article linked states:
The recently announced postponement in opening the new Crossrail subway line in London was attributed in part to problems with the signals.
Three different systems overlaid, with a fourth being used in some other way that escapes me right now...

There's irony in that Metrolinx is facing the same challenge:
  • #1
  • New GO Train Control+Signalling (PTC, CBTC, ETC) -- Safety & Subway-Like Frequency
UPDATE: New November 22, 2017 News:

GO is going to deploy ETCCS -- Enhanced Train Control and Conventional Signaling:
Parsons secures Metrolinx ETCS Contract

This is a hybrid between European ETCS and traditional railroad signalling. It has a moving-block upgrade path. ETCS Level 3 is equivalent to CBTC with moving-block ability. This means Metrolinx/GO is currently deploying a signal system upgrade path that keeps the door open to moving-block capabilities found in ultra-short-headway metro systems.

UPDATE: Post updated April 2016:

Hello,

GLOSSARY:
PTC = Positive Train Control
CBTC = Communications-Based Train Control (can also do positive train control safety responsibilities too).
ATC = Automatic Train Control, often piggybacked on PTC or CBTC

CBTC (or a variant) is now part of Metrolinx requirement for GO RER

Positive train control does an automatic slowdown/stop of your train for safety if train tries to exceed speed limit for any reason (grade, error, inattention, traffic) and/or if it detects known danger ahead (such as a train ahead, a curve ahead, TSOs, PSOs). This saves everybody's asses when the train driver does not manually slow down the train on time for any reason.

Shorter Headways
These requires more advanced control systems. All major RER systems worldwide with tight headways (e.g. 3-minute, 5-minute) now use an enhanced control system such as PTC or CBTC or an Europe variant called ECTS. Paris RER, German S-Bahn, all use variants of these systems. The GO $13.5bn electrification budget includes the cost of this upgrade. Such systems are particularly important for the "SmartTrack" route of GO RER, which may have the tightest headways on the GO network.

TTC Uses It
TTC already has been using a PTC variant for a long time. They are upgrading to CBTC to allow ~2-minute headways on Yonge. The addition of the system to GO's system is one of the pieces necessary to make GO feel more like a metro system, similar to other RER/RER-like systems worldwide.

GO already is researching 5-minute headways on some RER routes (like the "SmartTrack" routing)
Several Metrolinx documents mentions 5-minute headways on some RER routes (like the SmartTrack route). While there is a lot of debate whether or not this is possible with the first $13.5bn of GO RER, there is definitely no doubt given sufficient money, a CBTC system makes this path possible as has already occured elsewhere in the world.

How much is PTC or CBTC?
The assumed cost of installing CBTC into the GO network is estimated by Metrolinx to be $800 million, embedded as part of the existing $13.5bn GO RER/electrification budget. PTC is estimated only $200 million, but Metrolinx is planning on going beyond and planning CBTC for RER.

Saves Lives / Amtrak Disaster
With the Amtrak disaster, and the fact that positive train control would have prevented deaths:
www.npr.org/sections/thetwo-way/2015/05/14/406652406/positive-train-control-the-tech-that-couldve-prevented-amtrak-derailment
www.cnn.com/2015/05/15/us/philadelphia-amtrak-train-derailment/
The train and track was equipped with this safety system, but wasn't turned on yet because they hadn't yet gotten permission to turn on the train control radios yet (radio frequency permission issue)!

Automatic Train Control?
This is often an optional feature of advanced train control systems (variants of PTC and CBTC). GO will not use this unsupervied due to unions and safety issues, especially given platform overcrowding, but the technology provides that option for some systems worldwide. In reality, automation is like an autopilot, which the train driver supervises. This is a speed optimizer, to keep a train more easily in its headway between trains, accelerating and decelerating precisely.

Union Station Bottleneck?
Recent 2015-2016 Metrolinx documents mention other planned major upgrades (Union Station Rail Corridor) plan to increase train throughput at Union station to approximately 50 trains per hour (by ~2031). This includes 45mph crossovers in the east and 30mph crossovers in the west. With this speed and signalling upgrades made available, combined with CBTC, trains will no longer need to crawl slowly towards Union for several minutes before entering the beginning of a Union platform. Combined with short-dwelling, and (potentially expensive) optimizations elsewhere, this potentially allows at least one combined route to have approximately 5-minute same-platform headways at Union, presumably on one of the wider platforms. Whether the debate of ultimate headways are 15-minute or 5-minute, it is assumed that headways will progressively decrease as upgrades are rolled out, and will likely further continue beyond the initial completion from the $13.5bn GO RER budget.

GO RER requires CBTC -- See Newer Post
The short headways in GO RER objectives require very tight train headways. During frequent train services, this can mean increased risks and safety issues (collisions, etc). CBTC will help greatly permitting trains to follow trains at braking distances. TTC, and many other frequent-service subways, already has positive train control on their subway train for a very long time now, and are upgrading to CBTC.

How urgently should positive train control / communications based train control arrive on GO's network? Let's discuss.


Perusing some of the hits I've found on Google, some software sources talk of a software algorithm "parabolic curve" to ease the CBTC (ATC) controlled trains into a Moving Block section, the 'rate of curve' configured to slow the trains to a speed and headway such as to ease them into the Moving Block sequence without bunching. How difficult is that? Phhhh...I hope for an answer from the traffic engineers already tagged above.
 
Last edited:
^ Further to the Crossrail reference:
12 NOVEMBER 2018

ANALYSIS
Crossrail: what’s the hold-up with London’s long-awaited line?
[...]
Signalling has long been seen as a particular issue for the Elizabeth Line, which mixes conventional systems and state-of-the-art ones across its length. The section between Paddington and Heathrow uses the European Train Control System (ECTS); west of Heathrow and east of Stratford, the train uses an automatic warning system, combined with a train protection warning system. And lastly, the central section uses a modern communications-based train control system.

The issue was raised in the past; back in 2015, The Independent reported that engineers and rail experts were struggling to create ‘interfaces’ that would allow trains to switch from legacy signalling systems to newer ones.

At a Westminster Public Forum event in October, Crossrail’s head of technical assurance John Crosfield said that the integration programme was still a massive challenge. “Getting the integration right is key to getting this delivered,” he said.

However, another delegate at the forum who wished to remain anonymous said that that it was unlikely the delay was all down to dynamic testing, as the delayed Paddington to Abbey Wood section is essentially a ‘self-contained’ railway without any interfaces to the other Crossrail elements.

“True, the Siemens CBTC control system that will control movements in the central core is not being tested, but that is a proprietary system that has been deployed in many metro systems elsewhere,” the delegate said. “Getting all the station facilities right at this stage should be well advanced and even if the odd escalator is not ready, it should not be a show stopper.” [...]
https://www.railway-technology.com/features/crossrail-delay-rail/

The Independent reference above is at:
Crossrail faces the prospect of signal trouble from ... - The Independent

If the problems are as abject as posters above observe, and it's not just a temporary teething issue, the TTC might do well to 'ask some questions' as to better integrating the the two systems until the project is finished.
 
^ Further to the Crossrail reference:

https://www.railway-technology.com/features/crossrail-delay-rail/

The Independent reference above is at:
Crossrail faces the prospect of signal trouble from ... - The Independent

If the problems are as abject as posters above observe, and it's not just a temporary teething issue, the TTC might do well to 'ask some questions' as to better integrating the the two systems until the project is finished.

The situation is also compounded by the ongoing early closures. Train turnbacks plus two different systems causes one hell of a delay.
 
The situation is also compounded by the ongoing early closures. Train turnbacks plus two different systems causes one hell of a delay.
If CBTC is 'landing' more trains at the beginning point of Moving Block....then I have to question where the extra stock is coming from? Unless I'm misunderstanding what's happening, and why, then it seems extra stock must be added in to test the 'capacity' yield and sustainability of the new ATC segment, because the TTC doesn't have enough compatible stock to run the whole line ATC at the capacity potential of ATC.

Perhaps the answer is to end the 'testing' phase and run only as much stock that when headwayed to mesh with the Moving Block section, doesn't present a 'bunching up' at transition point.

This presents a bit of a conundrum though, as ostensibly time to destination on the ATC section will be shortened, but throughput will remain the same as with ATC. (Edit: Whoops..."As with Moving Block")
 
Last edited:
Essentially there is a bottleneck at the conversion point between ATC and block signals. This leads to backups along the line. You have a ton of trains tightly packed from Vaughan to St Patrick but wider headways south. This leads to problems.

They should have done the conversion as a whole before turning the system on but alas they did not.

There isn't a bottleneck at the migration point, at least not one that you would really notice at that time of the day. (Although I will say that technically you are correct that there is a potential bottleneck there. But the likelihood of it being a major issue in the long run is pretty minimal, as there are other locations that are far bigger bottlenecks to the flow of trains.) The amount of time it takes for a train to enter or exit the ATO is pretty minimal, and far, far less than it takes the signal system to clear a train through a crossover, for instance.

What you saw was just bad luck, unfortunately. I had to wait over 10 minutes for a train northbound at King at 10pm on Monday - meanwhile southbound trains were streaming through as usual with no delays whatsoever. I suspect that by the time the time you got into the system whatever delays I had to deal with earlier had propagated to catch you in the other direction.

It's everything from St. Patrick to Vaughan now isn't it?

'tis.

Still, your point holds. The answer is they don't. They are just trying to hold the existing schedule. They can't start tightening the scheduled spacing until after they finish the entire line (unless they just want to run some trains on part of the line - but this isn't the section with the higher demand, so they won't.

That's not specifically true.

They can operate trains more "efficiently" through the ATC/ATO than they can through the old fixed-block system, because they can run the trains closer together between the stations, and stack them closer together at stations. This is even more important at VMC, where the backups are much less severe than they are at Finch. They haven't yet, but they could start reducing the round trip time tomorrow if they wanted to, and to a degree they already have - a lot fewer crews are having to deal with forced overtime due to their trains running late.

Dan
 
They can operate trains more "efficiently" through the ATC/ATO than they can through the old fixed-block system, because they can run the trains closer together between the stations, and stack them closer together at stations. This is even more important at VMC, where the backups are much less severe than they are at Finch. They haven't yet, but they could start reducing the round trip time tomorrow if they wanted to, and to a degree they already have - a lot fewer crews are having to deal with forced overtime due to their trains running late.

Dan

Will they move to a one person train operation (or zero) from St Patrick going North? Now that slightly over 1/2 of the time for Line 1 is on ATC/ATO can we reduce the cost of operation by eliminating the needs for the operator (or two)? Have them get off at St Patrick, cross over and then wait for their turn going southbound.
 
Will they move to a one person train operation (or zero) from St Patrick going North? Now that slightly over 1/2 of the time for Line 1 is on ATC/ATO can we reduce the cost of operation by eliminating the needs for the operator (or two)? Have them get off at St Patrick, cross over and then wait for their turn going southbound.

Definitely not zero. Even the RT which is computer controlled has 1 operator incase all hell breaks loose.
 
That's not specifically true.

They can operate trains more "efficiently" through the ATC/ATO than they can through the old fixed-block system, because they can run the trains closer together between the stations, and stack them closer together at stations. This is even more important at VMC, where the backups are much less severe than they are at Finch. They haven't yet, but they could start reducing the round trip time tomorrow if they wanted to, and to a degree they already have - a lot fewer crews are having to deal with forced overtime due to their trains running late.
Good point, they could do that ... though I don't think they can do much about frequency until the whole line is done. And on average the trains wouldn't be any closer together if operating faster - but yes should help terminal operations.

Now you've said that, I'm wondering why they hadn't tried that already.
 
Definitely not zero. Even the RT which is computer controlled has 1 operator incase all hell breaks loose.

The operator is there on the RT as per the Toronto Union's insistence.

The same exact technology has worked in Vancouver with completely driverless trains since 1985
 
Will they move to a one person train operation (or zero) from St Patrick going North? Now that slightly over 1/2 of the time for Line 1 is on ATC/ATO can we reduce the cost of operation by eliminating the needs for the operator (or two)? Have them get off at St Patrick, cross over and then wait for their turn going southbound.

They probably wont change the crew levels to one operator until the entire line is ATC.

And then eventually go to completely driverless, but it will have to be a modification of the union rules. However I could see this happening with the subway upload to the province. The TTC union is not coming along for the ride.

Thats part of the efficiencies the province is touting for the subway upload. However they dont use the word union because their voter base is heavily working class.
 
Will they move to a one person train operation (or zero) from St Patrick going North? Now that slightly over 1/2 of the time for Line 1 is on ATC/ATO can we reduce the cost of operation by eliminating the needs for the operator (or two)? Have them get off at St Patrick, cross over and then wait for their turn going southbound.

No. The equipment is not yet installed to allow them to run with one-person crews on the YUS.

Dan
 
The same exact technology has worked in Vancouver with completely driverless trains since 1985

That line was also conceived and built to be unmanned. The same can not be said about the TTC's subway, and the cost of the work involved to do that would likely dwarf the cost of resignalling the line.

Dan
 

Back
Top