NSW Future Rail Plan - NWRL/Metro/Harbour Crossing

 
  darcyj Chief Train Controller

Warabrook to Beresfield on the limited stops pattern is the quickest pair I am aware of.  11.1 track kilometres in seven minutes,
donttellmywife
Blacktown to Penrith, 20.22km, is timetabled at 14 minutes for express (Blue Mountains) services but trains regularly beat that, and doing it in 12 minutes would be faster than the above.  I was on one a couple of weeks ago - W561 - which covered Parramatta to Penrith (31.88km) in 19 minutes.

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  djf01 Chief Commissioner

I strongly suspect it is this too.  I don't see why automation would make a difference though.
donttellmywife
A top speed of 80kph is pretty low, suggesting something less than a stellar power:weight, as you would expect given most applications of monorails.

AFAIK, fully automated systems typically have a fixed interval dwell.  For low patronage (ie theme park rides), or point to point applications like airport shuttles, this isn't a great drama.  But for higher loadings it's potentially an issue.  The fixed dwell needs to be long enough to cope with a lot of boardings, and a blanket 30 seconds might not be enough, even though it might be a perfectly appropriate mean dwell time if there is manual intervention.   Sao Paulo has a population of 25mil, vs Copenhagen's 1mil.
  donttellmywife Chief Commissioner

Location: Antofagasta
A top speed of 80kph is pretty low, suggesting something less than a stellar power:weight, as you would expect given most applications of monorails.

AFAIK, fully automated systems typically have a fixed interval dwell.  For low patronage (ie theme park rides), or point to point applications like airport shuttles, this isn't a great drama.  But for higher loadings it's potentially an issue.  The fixed dwell needs to be long enough to cope with a lot of boardings, and a blanket 30 seconds might not be enough, even though it might be a perfectly appropriate mean dwell time if there is manual intervention.   Sao Paulo has a population of 25mil, vs Copenhagen's 1mil.
djf01
I wondered if the low speed was due to mechanical wear or vehicle stability.

Showing my ignorance here, but I always assumed that the automated systems still had some sort of human intervention to decide when they were right to close doors and depart (that human doesn't have to be local to the train or station).  Perhaps clearance detection systems are smarter than I give them credit for.
  darkmage35 Station Master

Location: Canberra
Another aspect is that when a manufacturer says "up 80 km/h", they might be getting a little hypothetical at the upper end of that range.
donttellmywife
Copenhagen metro and Tokyo monorail top speeds are both 80km/h, and Osaka monorail top speed is 75km/h. The top specified speed is typically listed as "top service speed", not the top speed the vehicle is actually capable of, so I don't think this is an issue either. It certainly isn't for heavy rail or maglev. Non uniform acceleration is a more interesting question.

Warabrook to Beresfield on the limited stops pattern is the quickest pair I am aware of. 11.1 track kilometres in seven minutes
donttellmywife
Ah, I see now. I was looking at the timetable the other way, and Beresfield to Warabrook is timetabled at 8 minutes.

A top speed of 80kph is pretty low, suggesting something less than a stellar power:weight, as you would expect given most applications of monorails.
djf01
Metro top speeds aren't much higher, typically being 80-100km/h.

Sao Paulo has a population of 25mil, vs Copenhagen's 1mil.
djf01
And Tokyo has a population of 8.9mil, and Osaka of 2.6mil, but as far as I can tell the dwell times are 30s and 60s respectively. That implies a looser relationship than you'd think, but 25mil could explain it, yeah. 30 seconds should be fine for Sydney, especially since some of the route is already covered by nearby heavy rail.
  donttellmywife Chief Commissioner

Location: Antofagasta
Ah, I see now. I was looking at the timetable the other way, and Beresfield to Warabrook is timetabled at 8 minutes.
darkmage35
The difference is notionally due to the need to slow to 80 to get around the Hexham platform curvature.
  djf01 Chief Commissioner

I wondered if the low speed was due to mechanical wear or vehicle stability.

Showing my ignorance here, but I always assumed that the automated systems still had some sort of human intervention to decide when they were right to close doors and depart (that human doesn't have to be local to the train or station).  Perhaps clearance detection systems are smarter than I give them credit for.
donttellmywife
Another possibility might be gearing.  Monorails run on little shopping trolly casters, so they probably naturally have low gearing.

As for human intervention, yes most automated systems do have human intervention, usually by a driver Smile.  

To take the suggestion slightly seriously for a moment, I think maglev aside, monorails really only offer an aesthetic rather than functional engineering difference over other conventional transport guideways.  Hence there application primarily in places where a "futuristic appearance" has some significance.  Flanged steel wheels on steel rails is original and still the most popular method, and there are good reasons for this.
  darkmage35 Station Master

Location: Canberra
To take the suggestion slightly seriously for a moment, I think maglev aside, monorails really only offer an aesthetic rather than functional engineering difference over other conventional transport guideways.  Hence there application primarily in places where a "futuristic appearance" has some significance.  Flanged steel wheels on steel rails is original and still the most popular method, and there are good reasons for this.
djf01
Sheesh, it's like almost nobody here knows anything about the technology. Of course there are functional engineering differences.

The guideways for a monorail are lighter and narrower than for metro (or any ordinary elevated steel rail), which means cheaper, requires less space on the ground for supports, and casts less shadow. The primary application is where there isn't enough space on the ground for at-grade and tunnelling is too expensive. Steeper grades are also easier to handle, but depending on the light rail vehicle that advantage may be slim to non-existent.

The disadvantages are that whenever an alignment is mostly at-grade or underground, ordinary rail is cheaper. Switching is also more complicated with monorails (takes about 9-12 seconds to switch by bending a section of beam). You also have to have the entire thing be grade-separated, which usually isn't a problem because level crossings are a liability for everything except buses and light rail anyway.
  fixitguy Chief Train Controller

Location: In Carriage 4 on a Tangara
Sheesh, it's like almost nobody here knows anything about the technology. Of course there are functional engineering differences.

The guideways for a monorail are lighter and narrower than for metro (or any ordinary elevated steel rail), which means cheaper, requires less space on the ground for supports, and casts less shadow. The primary application is where there isn't enough space on the ground for at-grade and tunnelling is too expensive. Steeper grades are also easier to handle, but depending on the light rail vehicle that advantage may be slim to non-existent.

The disadvantages are that whenever an alignment is mostly at-grade or underground, ordinary rail is cheaper. Switching is also more complicated with monorails (takes about 9-12 seconds to switch by bending a section of beam). You also have to have the entire thing be grade-separated, which usually isn't a problem because level crossings are a liability for everything except buses and light rail anyway.
darkmage35

i know the technology. its just not right for Sydney. + there is always NIMBY. so its either going to be a tunnel for heavy rail (least desruptive to NIMBY people. they cant possiblty object to a tunnel), light rail (only objectionable if it runs on narrow streets) and at grade heavy rail (buying buildings/houses and tearing roads make it desruptive and NIMBY comes in again as the area is pretty built up)
  darkmage35 Station Master

Location: Canberra
i know the technology. its just not right for Sydney. + there is always NIMBY.
fixitguy
Heavy rail at-grade means NIMBY, buying up and knocking down a lot of real estate, etc. These are serious problems because it takes longer to build than the typical term of government.

Tunnels are expensive. Typical costs seem to range from $300 million/km for suburban through to $1 billion/km for tunnels under the CBD or the deep areas of the harbour.

Light rail is only really suitable in CBDs and where there are roads that are significantly wider than necessary, meaning spare space yet a ton of level crossings from cross streets. This has limited use in Sydney, the most obvious example being Anzac parade. Light rail is more suited to a place like Canberra.

You could always just focus on upgrading the existing corridors in the transport network, but there are significant gaps. Since the NWRL is going to be built along with the CBD/southeast light rail, the two remaining big ones are the Carlingford line and the northern beaches.

Hence, monorail. NIMBY is actually of slightly lesser concern here, because like light rail it can be constructed on a timescale more in line with a term of government. Less opportunity to block it, should there be the political will for it. The street layout also just barely gives rise to a suitable corridor.

Where, if anywhere, would you consider monorail tech to be suitable?
  donttellmywife Chief Commissioner

Location: Antofagasta
Sheesh, it's like almost nobody here knows anything about the technology. Of course there are functional engineering differences.

The guideways for a monorail are lighter and narrower than for metro (or any ordinary elevated steel rail), which means cheaper, requires less space on the ground for supports, and casts less shadow.
darkmage35


Oi... those who assume constant acceleration (despite the progressive increase in power requirement with speed) should be a little careful about casting stones about knowledge.

To a first approximation, structure requirements for a vehicle travelling at a certain speed are determined by the mass of the vehicle.  For the same passenger capacity (or floor area) why is the mass of a monorail vehicle so much less than a conventional vehicle?

The primary application is where there isn't enough space on the ground for at-grade and tunnelling is too expensive. Steeper grades are also easier to handle, but depending on the light rail vehicle that advantage may be slim to non-existent.

The disadvantages are that whenever an alignment is mostly at-grade or underground, ordinary rail is cheaper. Switching is also more complicated with monorails (takes about 9-12 seconds to switch by bending a section of beam). You also have to have the entire thing be grade-separated, which usually isn't a problem because level crossings are a liability for everything except buses and light rail anyway.
Lack of compatibility with existing systems and the uniqueness of the vehicle/guideway interface is also a disadvantage against a light rail or heavy rail solution.  If you are not running at grade, then station complexity/accessibility is also not great.

There are lots of public transport systems in the world.  Not many of them are monorail, despite the "technology" having been around for a while.  Perhaps that's because this is the dawn of a new era, but at the same time it does give cause for scepticism.

Looking at your map again I'd also think you'll find speed limits associated with the radius of curvature of the track would be significant.  Map the track across into a curve diagram and then set a speed for each curve (you can use a limiting lateral acceleration (associated with passenger comfort/safety limits, not structure limits) as a guide), then run transit time calculations considering acceleration and de-acceleration.
  djf01 Chief Commissioner

Where, if anywhere, would you consider monorail tech to be suitable?
darkmage35
Disneyland?
  darkmage35 Station Master

Location: Canberra
Oi... those who assume constant acceleration (despite the progressive increase in power requirement with speed) should be a little careful about casting stones about knowledge.
donttellmywife
The assumption was that the specified acceleration was the average acceleration from a complete stop to travelling at top service speed. If you have a better suggestion on how to interpret the specs, by all means, let's hear it. I'd think that interpreting it any other way would imply the manufacturer was being dishonest.

To a first approximation, structure requirements for a vehicle travelling at a certain speed are determined by the mass of the vehicle. For the same passenger capacity (or floor area) why is the mass of a monorail vehicle so much less than a conventional vehicle?
donttellmywife
That says very little about the width of the required structure and hence the shadow cast. Even though they have to support similar weight, an elevated metro track is wider and flatter while a monorail track is narrower and taller and incorporates more of the supporting structure into the track itself. Basically, a monorail track is more optimal for elevation than a normal steel rail track for the same reasons that monorail is more expensive than steel rail when on the ground.

Light rail vehicles tend to be a bit heavier for what they are because they usually aren't grade-separated and have to cope with potential collisions. Heavy rail vehicles are just larger and faster.

Lack of compatibility with existing systems and the uniqueness of the vehicle/guideway interface is also a disadvantage against a light rail or heavy rail solution. If you are not running at grade, then station complexity/accessibility is also not great.
donttellmywife
Lack of compatibility with existing systems isn't a problem. Interchanging between light rail, heavy rail, monorail and metro are all about equally as difficult, and for reliability purposes it's better to have a sectorised system anyway. The not running at-grade also isn't as big a problem as you'd think, because heavy rail often requires walking up and down stairs to access anyway due to island platforms. Light rail is the odd one out here, where you're more or less always able to just walk directly up to it like a bus stop.

There are lots of public transport systems in the world. Not many of them are monorail, despite the "technology" having been around for a while. Perhaps that's because this is the dawn of a new era, but at the same time it does give cause for scepticism.
donttellmywife
Or perhaps that's because well planned cities or those that have plenty of space along transport corridors don't usually need an elevated rail system. I did say that the primary application was when there isn't any space on the ground and tunnelling is too expensive.

Or perhaps your use of quotes around "technology" means you have an irrational bias here.

Looking at your map again I'd also think you'll find speed limits associated with the radius of curvature of the track would be significant. Map the track across into a curve diagram and then set a speed for each curve (you can use a limiting lateral acceleration (associated with passenger comfort/safety limits, not structure limits) as a guide), then run transit time calculations considering acceleration and de-acceleration.
donttellmywife
Remember when I said there were only 3 sharp corners not near stations between Parramatta and Central? That's what I was referring to. Assuming a max cant of 10 degrees (perfectly reasonable for a monorail) and a max lateral acceleration of 0.1g, the top speed around a 46m radius curve is about 40km/h. To travel at 80km/h, the radius has to be more around 170m. Corners that I consider to be sharp are those that require radii below around 170m.
  viaprojects Train Controller

Lack of compatibility with existing systems isn't a problem. Interchanging between light rail, heavy rail, monorail and metro are all about equally as difficult, and for reliability purposes it's better to have a sectorised system anyway. The not running at-grade also isn't as big a problem as you'd think, because heavy rail often requires walking up and down stairs to access anyway due to island platforms. Light rail is the odd one out here, where you're more or less always able to just walk directly up to it like a bus stop.




darkmage35
lol. every station on the sydney monorail had a problem with interchanging between modes of transport and it's only a small verison of the oversea versions.

give up the idea of monorail. too many problems with the system. as you can have a single fail in the system and the whole network is shut down. sydney has been there and done it many time's.
we also found out the monorail's cannot climb hills.
  darkmage35 Station Master

Location: Canberra
we also found out the monorail's cannot climb hills.
viaprojects
You see? See what I mean? Wilful ignorance and irrational bias.
  viaprojects Train Controller

You see? See what I mean? Wilful ignorance and irrational bias.
darkmage35

it's fact for sydney monorail. try the newspaper archives.
  darkmage35 Station Master

Location: Canberra
it's fact for sydney monorail. try the newspaper archives.
viaprojects
Uh huh. Meanwhile, the Sydney monorail was actually spec'd at 4.5% gradient up, 6.5% gradient down, most modern monorails are spec'd at 6-10% max gradients, and we aren't even considering varying the height of the supports to smooth it out some. Consider the following, if you will: http://i42.tinypic.com/35b8mcp.jpg

Your other comments were similarly ridiculous.
  donttellmywife Chief Commissioner

Location: Antofagasta
Or perhaps your use of quotes around "technology" means you have an irrational bias here.
darkmage35
It was quoted because there are a multitude of technologies potentially at play, some of which are vendor specific.  Whether I have an irrational bias is a separate question - if I do, then I don't think I am alone...


Remember when I said there were only 3 sharp corners not near stations between Parramatta and Central? That's what I was referring to. Assuming a max cant of 10 degrees (perfectly reasonable for a monorail) and a max lateral acceleration of 0.1g, the top speed around a 46m radius curve is about 40km/h. To travel at 80km/h, the radius has to be more around 170m. Corners that I consider to be sharp are those that require radii below around 170m.
For track dedicated to a particular service, the maximum cant is set by passenger comfort in the event that a service stops on the section. Something like 6% is typical.

I looked at your map and saw more than three curves that I figured would have some sort of line speed limit.  I didn't get out a ruler and measure them, or hence subsequently determine what sort of speed would apply.

I think a useful model for vehicle acceleration is for tractive effort (or acceleration, unless your vehicle is losing mass, like a rocket...) to be constant up until some speed (because you are limited by something like occupant comfort, or adhesion, or traction motor current, or ...) then tractive power to be limiting up until the vehicles maximum design speed (because you are limited by the power supplied to the traction system in some way).  I have no idea what sort of numbers apply to your monorail.
  viaprojects Train Controller

Uh huh. Meanwhile, the Sydney monorail was actually spec'd at 4.5% gradient up, 6.5% gradient down, most modern monorails are spec'd at 6-10% max gradients, and we aren't even considering varying the height of the supports to smooth it out some. Consider the following, if you will: http://i42.tinypic.com/35b8mcp.jpg

Your other comments were similarly ridiculous.
darkmage35
the real section to consider is the section from qvd to Darling Park station.

edit city to darling park has a grading of 6.5%  http://www.otsi.nsw.gov.au/rail/Investigation-Report-Veolia-Darling-Park-Monorail-Collision.pdf
  darkmage35 Station Master

Location: Canberra
For track dedicated to a particular service, the maximum cant is set by passenger comfort in the event that a service stops on the section. Something like 6% is typical.
donttellmywife
This is news to me. Before I started looking at monorails, I was musing about high speed rail. The German ICE is spec'd at about 7 degrees max cant, for example, and that's 12.3% right there. I got the general impression that for sections of track where any stopping would be due to some sort of breakdown or system malfunction, the cant was limited more by the physical capabilities of the vehicle to stay on the rails, not by passenger comfort.

I think a useful model for vehicle acceleration is for tractive effort (or acceleration, unless your vehicle is losing mass, like a rocket...) to be constant up until some speed (because you are limited by something like occupant comfort, or adhesion, or traction motor current, or ...) then tractive power to be limiting up until the vehicles maximum design speed (because you are limited by the power supplied to the traction system in some way). I have no idea what sort of numbers apply to your monorail.
donttellmywife
Quite right. Trouble is that the only graphs I've been able to find that show this sort of thing apply, again, to high speed rail.
  Alfred3333 Locomotive Fireman

The problem is that the regular Sydney commuter assumption would be that the monorail is useless, unreliable and inconvenient. It's the recent removal of the monorail line in Sydney that is all to blame. It was indeed a negative example of the modern monorail. I don't think many would want a monorail line in Sydney in the near future, even if it is up to modern standards. The image of the unreliable monorail in the past have changed Sydney's image of a monorail, the benefits and the positives.
  darkmage35 Station Master

Location: Canberra
Ah, here we go. A video of an existing (quite old) monorail system that shows how tilted they can get. I think this appears to be around 6 to 8 degrees, but I could be wrong.



http://www.youtube.com/watch?v=cVXfW17C4ic
  donttellmywife Chief Commissioner

Location: Antofagasta
This is news to me. Before I started looking at monorails, I was musing about high speed rail. The German ICE is spec'd at about 7 degrees max cant, for example, and that's 12.3% right there. I got the general impression that for sections of track where any stopping would be due to some sort of breakdown or system malfunction, the cant was limited more by the physical capabilities of the vehicle to stay on the rails, not by passenger comfort.

darkmage35
No - you are right - that was a degrees/percent cock-up on my part.  6 degrees is typical.
  darkmage35 Station Master

Location: Canberra
No - you are right - that was a degrees/percent cock-up on my part.  6 degrees is typical.
donttellmywife
Some subsequent searching has turned up suggestions that, through special waivers, there are spots in the US with 7 degrees and spots in Europe with 11.8 degrees of cant. (Given standard gauge the inches and degrees amusingly work out the same in these cases.) That's higher than I thought. It's kinda hard to find official sources on this though, so take it with a grain of salt.

http://zierke.com/shasta_route/pages/05curve-curve.html
http://www.dailykos.com/story/2011/01/16/936788/-Sunday-Train-Quiet-Progress-Edition-One-Superelevation-Cant-Deficiency
...and so on.
  viaprojects Train Controller

why are we talking monorail the set form of transport has been fixed . http://www.transport.nsw.gov.au/media-releases/north-west-rail-link-proposals-lodged-major-operating-contract
  fixitguy Chief Train Controller

Location: In Carriage 4 on a Tangara
why are we talking monorail the set form of transport has been fixed . http://www.transport.nsw.gov.au/media-releases/north-west-rail-link-proposals-lodged-major-operating-contract
viaprojects
maybe because someone proposed a new rail line connecting Hurstville to Mac Park and decided a monorail is best while everyone else disagrees.

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