Fast and loose: trains on the new north-west line predicted to run at 60 km/h
WHEN it comes to talking a big game, Sydney’s train planners are world class.
Consider this: the most recent prediction is that the north west rail link will deliver commuters from Rouse Hill to Chatswood at an average speed, including 12 stops, at about 60km/h.
This might be technically possible. But if the predicted speed, included in planning documents for the $9 billion project, is achieved it will make the link one of the fastest metro-style train lines in the world, quicker than feted metros in Hong Kong, Shanghai and Singapore.
Consider this: the most recent prediction is that the north west rail link will deliver commuters from Rouse Hill to Chatswood at an average speed, including 12 stops, at about 60km/h.
This might be technically possible. But if the predicted speed, included in planning documents for the $9 billion project, is achieved it will make the link one of the fastest metro-style train lines in the world, quicker than feted metros in Hong Kong, Shanghai and Singapore.
First up this reporter is comparing apple and oranges. The North West link is a heavy-rail link NOT “a Metro” per some of his cited examples/
The former Labor government made similar predictions for its ill-fated north west metro in 2008. Some planners struggled to believe those predictions, just as some struggle with the latest.
Labor’s ill-fated north west metro (in 2008) was exactly that a “Metro” style line, with steel wheels augmented by rubber tires or out-rigger solid or pump-up rubber wheels. It was designed as a deliberate union busting ploy of explicitly Not being under by existing union coverage.
The latest proposal for the north west rail link is to build it as a 23-kilometre extension to the 13-kilometre Epping to Chatswood rail line.
When finished, in about 2019, a private operator will run single-deck trains in a shuttle between Rouse Hill and Chatswood.
Planning documents for the line anticipate the total trip – 36 kilometres – to take 37 minutes.
The government insists this speed – about 60km/h , including eight stops on the north west rail link, and four on the existing Epping to Chatswood line – should pose no problem.
Here I would tend to agree with the government planners. My question is why so slow? Only 60km/h on a new line while the old freight network has large chunks at 80km/h?
This would be an impressive feat. One of the best metro lines in the world, Hong Kong’s Kwun Tong Line, for instance, runs through 14 stops for 16 kilometres at a total speed of about 35km/h.
Singapore’s North East Line takes over half an hour to travel for 20 kilometres, past 15 stops, at a speed of about 37.5km/h.
Both those example must have stations closer than a kilometre apart. Such short placement would give you no time for acceleration before you would be slamming the brakes on again to stop at the next station.
Rail experts and train manufacturers were reluctant to talk on the record about the travel times, as most have an interest in getting work on the project.
But one manufacturer said the speed might – might – be able to be achieved with top-of-the-line train technology, and very fast interchanges at all stops.
The manufacturers reluctance was probably in a large measure due the reporters obvious agenda of getting a good story!
Another rail expert said: ”The times don’t look kosher.”
This was partly because so much of the line will be in tunnel – 28 kilometres of the 36. The existing Epping to Chatswood line already has a maximum speed limit of 80km/h, and a number of segments demanding slower speeds.
It would be interesting to know exactly what those slower speeds are and why. Are the speed limits to do with what is safe for the existing / legacy rolling stock?.
”Once you go in tunnels you’ve got extra windage as the train pushes the air away,” the expert said.
This expert is a great example of “X” an unknown quantity of “spurt” drip under pressure. A decade ago what the “expert” is saying was true, but not today. He is obviously unaware of the French breakthroughs regarding this knotty aerodynamic issue. The answer comes from a counter intuitive extension to the tunnels with strange holes in them. Prior to the French discoveries their high speed trains use to subject onlookers to sonic booms as the pressure-waves ahead of trains broke the sound barrier! Now the pressure waves and booms are gone and the trains are travelling much faster through those same tunnels now with fancy mods!
Smaller tunnels create more wind resistance.
”The less free space you have got, the more windage,” he said. The north west rail link is being built with small tunnels.
Yes & No see above, depends on how they are done. Number of pressure escape chimneys? ….
Another consultant told the Herald to ask Transport for NSW to ”provide details of assumed dwells at each stop, acceleration rates, braking rates, maximum speeds and travel times (not counting dwells) between each station. If they can’t or won’t provide this, they’re hiding something.”
No kidding! Maybe their performance criteria for the tender evaluation.
A spokeswoman for Transport for NSW declined to provide details of assumed dwells at each stop, acceleration rates, braking rates, maximum speeds and travel times – not counting dwells -between each station.
Instead, the spokeswoman said the new line would have stations much further apart than comparable lines, allowing trains to operate at higher speeds for longer distances.
”There will be reduced dwell times on Sydney’s new single deck trains because they will have more doors than double-deckers and customers will be able to get on and off faster,” she said.
‘Modern trains have fast acceleration and deceleration rates – the exact train performance specifications are dependent on the final rolling stock procured for the project.”
All true. Would be nice to get a hold of the Expression of Interest, or Call for Tenders documents for the rolling stock.