TheTigerMaster
Superstar
SELTRAC is easily capable of that, and better, should the track configuration allow. A lot of the ATC/ATO products on the market can, too.
Hell, even the crappy old fixed-block signalling system on the Toronto subway can achieve that in sections, and for short spurts.
Dan
Yes, you can achieve 90 second headways, in short spurts, if everything goes perfectly. If everything goes perfectly…
This is the real world though, and everything will not go perfectly. I’d be impressed if there are any rapid transit lines with 90% utilization rates that reliably hit 90 second headways. That’s a very tough task when you have 50,000+ imperfect human passengers doing imperfect human things on your rapid transit system at any given time. Everything from passengers holding up doors, to poor passenger circulation in stations and trains will impact the headways.
We were discussing this same topic in this thread a few months ago. Someone posted a PDF document comparing headways and utilization rates of various rapid transit lines around the world. If my memory serves me correctly, the only systems that were able to consistently hit that target were high capacity systems with relatively low ridership. It’s easy to hit 90 second headways, even without ATO, when you have a transit system running empty trains, with few opportunities for passengers to screw up the operation. This used to happen all the time during the early days of Line 1, even without ATO. However, it’s a totally different situation on lines that will be at near 100% capacity like the Ontario Line. There is an inverse relationship between the utilization rate of a rapid transit line and reliably achievable headways.
You’d definitely know better than me though. I’d be really curious to know if there are any metro lines in the world that reliably achieve 90 second headways while also having a 90%+ utilization rate. I'm not really interested in systems that achieve this with lower utilization rates. I don't recall being finding any example, but I might very well be wrong
But even if this was achievable elsewhere, I still say it would be unwise to assume it would be replicated here in Toronto, simply due to the local culture. We all know commuters in Toronto have little reservation about holding train doors at stations. All the time at across the system, even when trains aren't all that crowded, I see train operators having to press the door close buttons multiple times due to passengers rushing the doors. The problem is so bad that the TTC has had to hire announcers to practically beg customers not to delay trains at Bloor-Yonge. A few of incidents of passengers delaying a train by 10 seconds will quickly erode away your theoretically achievable 90 second headways
Also, given how cheaply this line is being built, I don't have a ton of faith that these stations will be designed with proper circulation to eliminate the crowding that induces passengers to hold doors open. These stations will likely look a lot like the Line 1 stations, with few points of egress resulting in passengers lumping themselves in one part of the train or platform. We see this all the time on the Yonge Line, where the north end of trains will be crowded with passengers, while the south end is empty, because passengers refuse to move to the south end of the Line 1 platforms at Bloor-Yonge Station (this is because the transfer to the Line 2 platforms are at the north end of the platform). Even though the TTC's ATO system is fully capable of 90 second headways, and even if track geometries were modified to be compatible with 90 second headways, I don't believe for a second that we'd ever see rush hour services with 90 second headways on the TTC, unless we drastically reduced ridership and redesigned the Line 1 stations to allow for better passenger flow through stations. Perhaps that would be achievable off peak, when 90 second headways aren’t needed in the first place, but certainly not on peak in busy sections when those headways would actually be beneficial
So long story short, I think any claims that 90 second headways will significantly boost real-world capacity in Toronto needs to be taken with an incredible grain of salt. Just because a system is technically capable of it, doesn't mean it will ever actually happen when it's needed most (trains and platforms are full)
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