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tsgsjm
Junior Train Controller
Joined: Feb 26, 2007
Last Visited: Dec 2, 2008
Location: Sydney
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Posted: Sun Oct 12, 2008 3:11 pm
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All trains all stops, just crazy
We dont really need more tracks not many places where more could be laid anyway, we just need more passing points. Take East Hills, all I think thats needed is a passing point at say Riverwood there are places on other lines that could also be treated this way.
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Jahommed
Locomotive Fireman
Joined: Aug 02, 2008
Last Visited: Nov 29, 2008
Location: G set toilet
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Crazy-D
Junior Train Controller
Joined: Jan 01, 2005
Last Visited: Dec 2, 2008
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Posted: Sun Oct 12, 2008 4:06 pm
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Wouldn't running more trains as all stoppers waste trains?
I mean that in a similar fashion to how more padding means that more trains would be required to run the same amount of runs. Also, how major a turn-off would it be for some passengers with their trains taking another 10-20 minutes to get to their destination?
Surely, it'd function good in a smaller area, but once you stack the kms up it'd get uglier.
If I do guess right, and I don't reply within 6 hours you can assume "open floor."
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Jahommed
Locomotive Fireman
Joined: Aug 02, 2008
Last Visited: Nov 29, 2008
Location: G set toilet
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Posted: Sun Oct 12, 2008 4:18 pm
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Take a look at the North Shore Line.......
Most of the trains are all stoppers there and the ones that aren't can sometimes take just as long as the all stoppers. Stopping at signals rather than stations.
The line runs so well when it works............ 
Tangara G sets are the best trains on the cityrail network.
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Incog_Neato
Station Master
Joined: Sep 09, 2008
Last Visited: Dec 1, 2008
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Posted: Sun Oct 12, 2008 9:48 pm
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| FieldShunt74 wrote: | | Davy wrote: | | Anyone know why it is 35 down near Petersham? |
That one stretches my "they know what they're doing" hypothesis to the limit.  |
IIRC the 35 is only on the Down Local, and it's due to a reduced clearance between the track and the concrete retaining wall.
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Warrick
Locomotive Fireman
Joined: Oct 10, 2008
Last Visited: Dec 1, 2008
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Posted: Sun Oct 12, 2008 11:02 pm
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Wow... wealth of knowledge here.
Now that i've got my head arounf Central-Strathfield... how about the Eastern Suburbs line from Martin Place? Anyone know the limits there and why?
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FieldShunt74
Chief Commissioner
Joined: Nov 06, 2004
Last Visited: Dec 2, 2008
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Posted: Sun Oct 12, 2008 11:33 pm
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| Warrick wrote: | | Now that i've got my head arounf Central-Strathfield... how about the Eastern Suburbs line from Martin Place? Anyone know the limits there and why? |
Welcome.
There are a number of existing threads on the ESR in general, and at least one recent offering on the perceived slowness of ESR services.
Why Martin place? The speed limit either side of that station, for a goodly distance in both direction, is 60km/h. That's also the maximum speed limit on the ESR, and aside from a few sections of 50km/h, represents the norm for the bulk of the line. A line with potentially tight headways between trains will necessarily have a lower speed limit than similar lines of lesser capacity. For trains of a given braking ability, the closer together you want to space them, the slower they need to travel to maintain safe separation by the signalling system.
It's like cars in traffic. If you're out on the freeway, you need to keep a good distance behind the car in front (unless you're a tailgating ejit) in order to be able to avoid rear ending them if they suddenly slam on the brakes. If you're just creeping along at slow speeds, you can close the gap considerably and still pull up short in an emergency. On a railway, the signalling system is designed with similar intentions, to stop the worst braking train before it can rear-end the train in front, based on the expected maximum speed, plus a margin for safety.
60km/h isn't too bad, the City Circle gets by with a general 40km/h limit.
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Oldfart
Chief Commissioner
Joined: Jan 01, 2006
Last Visited: Dec 2, 2008
Location: 21 miles from Griffiths Bros Teas
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Posted: Mon Oct 13, 2008 6:09 am
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| Crazy-D wrote: | W Also, how major a turn-off would it be for some passengers with their trains taking another 10-20 minutes to get to their destination?
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That might sometimes be true, but it doesn't necessarily follow. Many passengers will see their journey in total 'door to door' time and will often prefer a slower service pattern that departs regularly every few minutes than one which is a bit faster but for which they probably have to wait 10 to 15 minutes if they just turn up randomly at a station.
The time difference between an all stops and a limited stops service is also often less than imagined - East Hills to the City, for example has only a 6 minute difference, albeit that some passengers will perceive it as longer.
Higher frequency of commuter services means a passenger's total time to get from 'home to station to station to destination' is effectively reduced because of reduced waiting times and greater resilience against problems like their transport to the station running a bit late.
A man of great genius makes no mistakes; his errors are volitional and become the portals of discovery (James Joyce).
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aamslfc
Chief Train Controller
Joined: Mar 26, 2007
Last Visited: Dec 2, 2008
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Posted: Mon Oct 13, 2008 10:01 am
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| Incog_Neato wrote: |
IIRC the 35 is only on the Down Local, and it's due to a reduced clearance between the track and the concrete retaining wall. |
It would probably help things if the track was fixed up and didn't cause carriages to lean into the wall on that corner.
Incidentally, without wanting to sound like a broken record, Ashfield still has me perplexed. There are only a few turnouts on the Up/Down Suburban there and absolutely no crossovers (as in, crossing frogs or whatever those set-ups are called). What's more, they only seem to use those turnouts during trackwork or track inspections. As nadnerb said, the Summer Hill ones are 80, so either they're doing it to irritate us or there's some obscure operational reason for it.
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Grantham
Chief Commissioner
Joined: Apr 19, 2005
Last Visited: Dec 3, 2008
Location: I'm with stupid!
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Posted: Mon Oct 13, 2008 10:57 am
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The accident on page two had nothing to do with the points.
The City bound train was struck by the fourth or fifth car of the Ashfield bound train, which had derailed due to a broken Gibson ring, causing the steel tyre to come loose off the wheel.
The collision took place long before the initially derailed train reached the points.
M
Save oil, bring back steam. Vote #1 Bromage!
Lord High Minister to Lithgovia for Breweries and Bootlegging
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Warrick
Locomotive Fireman
Joined: Oct 10, 2008
Last Visited: Dec 1, 2008
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Posted: Mon Oct 13, 2008 11:17 am
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Thanks FieldShunt,
I'm new here, so i'll hunt down those old threads.
By your logic, it would imply that running single-deck stock with higher power to weight ratios and better breaking, rather than double deck suburbans, would allow for higher speed limits on the ESR. Of course, that the line doesn't have its own sector makes that impossible.
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FieldShunt74
Chief Commissioner
Joined: Nov 06, 2004
Last Visited: Dec 2, 2008
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Posted: Mon Oct 13, 2008 11:54 am
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| Warrick wrote: | | By your logic, it would imply that running single-deck stock with higher power to weight ratios and better breaking, rather than double deck suburbans, would allow for higher speed limits on the ESR. |
Yeah, maybe. You could run trains with consistently better braking performance at higher speed limits. You'd have to be careful to maintain passenger comfort. There's also the problem of the sizeable open air sections that get rained on. There's a huge difference between best braking on dry rails and what you could expect with misty rain. I don't know if the braking advantages of lighter vehicles under ideal conditions translates proportionally under worst case conditions or whether the lack of weight cancels out some of the gains. You still have to design for the expected worst braking train.
Lighter, faster stock would give quicker running times with no changes to the current speed limits. Get up to 60 sooner, brake later, quicker trip. The stations aren't all that far apart, and even if you could safely get 80km/h, you wouldn't gain great gobs of time, maybe a couple of minutes over the whole line, if you're lucky. Two minutes isn't a deal breaker for most passengers.
If you're saying that turning the ESR into a metro would increase capacity then you are probably correct.
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tsgsjm
Junior Train Controller
Joined: Feb 26, 2007
Last Visited: Dec 2, 2008
Location: Sydney
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Posted: Mon Oct 13, 2008 12:37 pm
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| aamslfc wrote: | | Incidentally, without wanting to sound like a broken record, Ashfield still has me perplexed. There are only a few turnouts on the Up/Down Suburban there and absolutely no crossovers (as in, crossing frogs or whatever those set-ups are called). What's more, they only seem to use those turnouts during trackwork or track inspections. As nadnerb said, the Summer Hill ones are 80, so either they're doing it to irritate us or there's some obscure operational reason for it. |
An old driver told me the overhead through there also has a lot to do with it, never really given it too much thought, board says 50 so that what I do.
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nadnerb_2000
Chief Commissioner
Joined: May 07, 2004
Last Visited: Nov 20, 2008
Location: between my hat and my shoe soles
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Posted: Mon Oct 13, 2008 12:51 pm
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| aamslfc wrote: | | Incog_Neato wrote: |
IIRC the 35 is only on the Down Local, and it's due to a reduced clearance between the track and the concrete retaining wall. |
It would probably help things if the track was fixed up and didn't cause carriages to lean into the wall on that corner. |
Actually - no. It would be entirely counter-productive. Your carriages would just lean the other way and you'd not be able to take that corner fast. Superelevation is there for a reason.
| Quote: | | Incidentally, without wanting to sound like a broken record, Ashfield still has me perplexed. There are only a few turnouts on the Up/Down Suburban there and absolutely no crossovers (as in, crossing frogs or whatever those set-ups are called). What's more, they only seem to use those turnouts during trackwork or track inspections. As nadnerb said, the Summer Hill ones are 80, so either they're doing it to irritate us or there's some obscure operational reason for it. |
They do get used on a daily basis. They have to be - if a set of points is not used in 72 hours they have to be inspected and certified fit for use before they can be used again, and thats a time consuming process.
Why the heck would they put a speed limit in to irritate people? Do you have some sort of mental image of some engineers sitting around a table, giggling, dreaming up ways to irritate people? More to the point - do you think passengers give a rats?
There could be a myraid of reasons the 50 is in place. Not just the crossovers. I've already mentioned that I suspect signal sighting distance could be a factor - the hume highway overbridge (I think it's the hume) hides the signals in both directions. You'd have to ask the engineers that put the speed limit in. Its been there for years - I noticed it as a kid. It could even be for passenger comfort - a lot of crossovers are rather rough at speed (the up and down mains just past Auburn come to mind).
And you'll never see trains on the suburban doing 80 over the summer hill ones. Accelerating from the 50, If you have a strong powering train the back of it may just clear the points as you're doing 65.
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simonl
Assistant Commissioner
Joined: Jan 05, 2006
Last Visited: Nov 16, 2008
Location: Brisbane
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Posted: Sat Oct 18, 2008 11:24 am
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| nadnerb_2000 wrote: | | You'd need to do a lot of engineering to get the track up to 115 - you'd need to rebuild the entire line. No joke - it would need an entirely new alignment. Trains would also be further apart so you'd be sacrificing frequency for speed. And as the city has sortof grown up - you'd need either the mother of all tunnels, or to bulldoze a heck of a lot of homes after buying them out for $800,000 a pop. Its not an economical way to save time. Oh - and you think people would put up with bustitution, road closures, home reposessions, billions of taxpayer dollars spent on saving a train 3 minutes? |
And if you're going to all that trouble, you should really be going to track suitable for 160km/h or more.
But I still think there are many kinks in the line which could be removed and boards could be raised. You save most of the time by getting rid of the slowest points, as we all know.
And regarding your point on Bustitution and road closures, didn't the M2 go under the train line at Epping without a single closure? Correct me if I am wrong.
| Quote: | | Want to compare notes with cities around the world? Have a look at Brisbane, things slow to a crawl in the city on the trains. |
You aren't wrong there! I largely blame the gauge for this. High speed points would be more difficult to use on narrow gauge. But I do quite like (not!) the way that the trains heading north from the Merivale bridge are forced to use the diverging leg of the turnouts to join the 4 tracks which head into Roma St Station.
| Quote: | | Even the JR East Bullet trains out of Tokyo does not exceed 110km/h until they pass Omiya (IIRC), over 30 kilometres away - mainly due to track curvature. A built for the purpose high speed line - on a massive concrete viaduct or in tunnel the whole way - with a low speed limit. |
Ouch!! I wonder why they did it that way? I sometimes why they picked standard gauge for the bullet train too, given that it was already incompatible with their existing network, but that's getting a bit off topic.
| Quote: | | the City West Link is complete. So your argument is already out of date. |
No kidding. But that strengthens the argument!
| Quote: | | Quote: | | Of course, this is largely due to waiting and walking times, but even the time on the train is only slightly faster than when I was driving in the peak. |
So - wouldn't it make more sense to reduce the waiting time? If you can cut a 15 minute wait down to 5 minutes, thats a better saving than 3 minutes you'd save with a major track reconstruction. Thats why metros and such work so well - its not the speed that counts, its the frequency. Though as people keep telling me, there arent really the paths available to achieve this on the current sydney system (though I think with in cab signalling and more standardised stopping patterns it could be done a little better). |
The average wait for a 15 minute frequency is 7.5mins and for a 5 minute frequency is 2.5 mins. So you're talking about a 5 minute saving requiring tripling the amount of services, which is only realised by those who can't read a timetable. I personally don't mind reading a timetable, and would rather save the 3 minutes or whatever on the train, but I see I'm in the minority on this point in here, with Oldfart agreeing with you on this point.
It's where the frequency is below every 15 minutes that more trains really make a difference. I was on a City-Hornsby via Strathfield train last night at 11pm, and I estimate that there were 500 people on the train. There is an argument that making it every 15 minutes (or even every 20 minutes) would increase patronage enough to justify the extra cost. I personally would like to see the defense of the 30 minute frequency when demand is this high - you don't need to buy more trains as you need these in peak hour anyway.
While I strongly advocate a new signalling system, even I am under no illusions that it will allow triple the number of services to operate. Perhaps if you had significantly better brakes to boot, but I can't see the upgrades being enough. A new signalling system would remove this limitation though:
| FieldShunt74 wrote: | | A line with potentially tight headways between trains will necessarily have a lower speed limit than similar lines of lesser capacity. For trains of a given braking ability, the closer together you want to space them, the slower they need to travel to maintain safe separation by the signalling system. |
So you could adjust the speeds based on the headways required. In peak hour, run slower, but off peak you can speed up so long as the timetable doesn't bunch up the trains.
| Quote: | | simonl wrote: |
Are these points obsolete designs or something? All over the world trains do faster than 100km/h on the straight path through points and also (I believe) crossovers. |
There are plenty of places on the CityRail network where trains can go full speed over crossovers in the "normal" position. Even plenty of places where they can go at 80-100km/h when the points are in the reversed position (eg: rhodes, beverly hills, glenfield - and concord west . . .  ).
<snip>
I imagine one day they will probably upgrade them - hopefully replacing them with some more modern ones that will allow trains on the suburban to reach 80. |
Fair enough. I do have one question, though. What trains actually use the diverging leg of these points? Could they be replaced with plain track?
How about that nadnerb_2000? I almost agreed with you! Perhaps I'm getting melower in my old age.
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