NatalieFeb 1

I know this is anathema to a lot of people on here, but I really wish there was a real search of some kind. I’m looking for people posting about niche stuff and it’s too damn hard!

If you post about train control, especially CBTC, hi.

Show threadDr. SobekFeb 1

@xferok I'm going to poke @q @hopla @rail and @jon as people interesting in trains, in various ways.

I don't think I've seen any post about "CBTC" but there's definitely some expertise around trains in there.

Show thread210561 ✨ [Q]Feb 1
@Sobex @xferok @hopla @rail @jon I know a non zero amount of random facts about CBTC/ERTMS, but by no means an expert
Show threadJon Worth
@q Sorry but I know sod all about CBTC. I know a bit more about ETCS! @Sobex @xferok @hopla @rail
Feb 1 at 7:43pmWeb
Show threadDr. SobekFeb 1

@jon @q @xferok @hopla @rail

What does CBTC stand for, and what does it refer to, btw ? (Sounds like it is signalling related, but I can't place it)

Show threadJon WorthFeb 1
@Sobex @q @xferok @hopla @rail Communications-based train control. But mostly used for metros. And despite the rather generic name it is a standard. And the standard does have *some* things in common with how ETCS works.
Show thread210561 ✨ [Q]Feb 1
@jon @Sobex @xferok @hopla @rail but there are a few different CBTCs which are ofc not interoperable
Show threadJon WorthFeb 1
@Sobex @q @xferok @hopla @rail But you'd need to find someone who works on metro rail to really get into the detail of it, and city rail transport is not my specialism at all. Hence why I know no more than what CBTC is.
Show threadNatalieFeb 1
@Sobex @jon @q @hopla @rail communications based train control. It’s a train control regime in which trains are able to locate themselves along the right of way and communicate that to a central system, which in turn issues permission to move up to a specified point
Show threadDr. SobekFeb 1
@xferok @jon @q @hopla @rail Is "PTC", positive train control, in the US used to designate CBTC systems ?
Show threadNatalieFeb 1
@Sobex @jon @q @hopla @rail CBTC is a form of PTC, but they’re not coterminous. The PATH, a metro that is technically a mainline, has had its CBTC system certified as meeting its PTC requirement, for example, but really any system that can vitally stop a train upon violation of a signal or movement authority is positive train control.
Show threadNatalieFeb 1
The trip arms in the NYC (and other) subways can be considered a form of positive train control, because they will stop a train that violates its movement authority (ie passes a red signal)
Show threadNatalieFeb 1
Generally speaking, though, in the US, PTC refers to I-ETMS or ACSES, which are both systems that will stop a train if it overruns a red signal and enforce civil speeds, though they do so in very different ways.
Show threadDr. SobekFeb 1
@xferok @jon @q @hopla @rail Uhhh, so any reasonable signalling system is a PTC, and a signlling system that doesn't meet PTC seems rather unsafe, right ?
Show thread210561 ✨ [Q]Feb 1

@Sobex @xferok @jon @hopla @rail correct

the US didn't have this until recently

Show threadDr. SobekFeb 1

@q @xferok @jon @hopla @rail
The US has a terrible and unsafe rail infrastructure 😱 <pretends to be shocked>  .

What about Canada, surely they aren't using such unsafe and antiquated systems ?

Show thread210561 ✨ [Q]Feb 1
@Sobex @xferok @jon @hopla @rail Canada is basically an extension of the US rail network, Mexico even more so
Show threadDr. SobekFeb 1
@q @xferok @jon @hopla @rail Has't Mexico opened recent and modern lines recently though ?
Show thread210561 ✨ [Q]Feb 1
@Sobex @xferok @jon @hopla @rail about that https://www.youtube.com/watch?v=RzraZbnm_jU
Well There's Your Problem | NEWSBRIEF: Corredor Interoceanico Derailment

YouTube
Show threadDr. SobekFeb 1
@q @xferok @jon @hopla @rail 2h30 and a 3h video 🙀 (I don't have enough time for that, I need to start working on my faculty job applications (however unlikely they are to succeed this year))
Show threadNatalieFeb 1
@Sobex @q @jon @hopla @rail Canada has no form of PTC on its mainlines nor does it have a framework to eventually require it, iirc. It’s kind of nuts.
Show threadNatalieFeb 1
@Sobex @q @jon @hopla @rail it depends on how you’re looking at it, but the US mainline rail network beats Canada in nearly all respects. It’s better regulated, used more efficiently, generally higher capacity, and operated better. Canada’s rail network reflects its highly extractive economy, and is good at little more than getting unit goods to port.
Show threadErik Sandblom 🌻Feb 3
@xferok @Sobex @q @jon @hopla @rail Maybe @paige or @reece can tell me where to find an essay or a video about railway signalling in Canada. If the train driver runs a red light, does the train stop automatically?
Show threadReece MartinFeb 3
@eriksandblom @xferok @Sobex @q @jon @hopla @rail @paige on main lines? No. Which is a huge problem! This will be fixed if Go transit installs etcs at least for its territory and it strains
Show threadNatalieFeb 3
@reece @eriksandblom @Sobex @q @jon @hopla @rail @paige though any unequipped train still poses a threat and essentially makes the system unable to vitally assure safety
Show threadNatalieFeb 3
@reece @eriksandblom @Sobex @q @jon @hopla @rail @paige any system without positive stop assurance is only as safe as human operators are
Show threadReece MartinFeb 4
@xferok @eriksandblom @Sobex @q @jon @hopla @rail @paige Not necessarily
Show threadNatalieFeb 4
@reece @eriksandblom @Sobex @q @jon @hopla @rail @paige following an unequipped train is fine, but it becomes difficult to assure the safety of trains potentially in its path. Obviously still better to have PTC on some than none, but partial doesn’t fully reduce risk!
Show threadNatalieFeb 1
@Sobex @jon @q @hopla @rail more or less. If the system can stop a train who has violated its movement authority, it is a form of positive train control. This includes something like trip stops, PZB magnets, cab signals, etc. On (generally) western mainlines in the US, engineers were relied upon to observe and heed signals. Now, I-ETMS, which is GPS based, has been rolled out on nearly all of the national rail network and can enforce those signals (plus other safety stuff, like speed).
Show thread波鉄 (Hatetsu)Feb 1

@Sobex @xferok @jon @q @hopla @rail Well, Poland doesn't, we (well, the vast majority of us) live, thanks to the dedication of signallers, train drivers, and the introduction of the venerable Radio-Stop system, which allows remotely stopping all trains in the area by playing a specific repeating tone on the train radio with the push of a button.
This is actually going to be sort of an issue in the coming years as we've finally started rolling out digital train communication over GSM-R which apparently does not have that function (don't see any reason why it couldn't, but I guess it was decided ETCS would be responsible for controlling the brakes) while ETCS will be a longer time coming on many of these lines

(Also, AFAIK PTC is an exclusively North American term, ATP (Automatic Train Protection) is what is used for systems elsewhere, I think)

Show threadDr. SobekFeb 1
@HaTetsu @xferok @jon @q @hopla @rail I concur I've only heard PTC mentioned wrt US railways.
Show threadNatalieFeb 1
@Sobex @HaTetsu @jon @q @hopla @rail As is often the case in this industry, there are many terms that essentially mean the same thing.
Show threadNatalieFeb 1
@jon @q well ECTS seems to approach CBTC closer and closer every day!