Friday’s post on whether the Northwest Rail Link (NWRL) should be a metro generated a large volume of comments, sufficient enough to warrant a new post to present some highlights and respond to the points raised in them. It’s worth reading the original post for some context if you have not already done so.
“People have commented that the dwell time at Town Hall, the most densely used station is rarely more than one minute, loading and unloading takes less and trains wait for their timetable departure – this means that 2 minute headways through the existing City Tunnels are feasible. Halving the existing signal spacing on the North Shore Line and the Bridge would enable trains to run closer together.” – Dudley Horscroft
“If headways could be reduced to 2 minutes with improved signalling I believe that double decker stock will move more people per hour than single deck.” – moonetau
The argument here is that signalling will allow double deck trains to achieve the same frequency that moving to single deck would provide. The problem with that argument is that the same signalling would also improve the frequency of single deck trains, so single deck would still achieve greater frequency and lower headways than double deck. That is why the single deck Paris metro can run 40 trains per hour, while its double deck RER system runs 30 trains per hour.
“Certainly building the tunnels so that double deck trains will not be able to use the NWRL is crazy. It means that in the future someone will have to design future double deck trains to fit into the smaller diameter tunnels! Reports indicate that the reduction will be only 400 mm.” – Dudley Horscroft
Smaller tunnels remains the least defensible part of the NWRL as proposed. Concerns like this are justified.
NWRL decisions are political
“It is easy to criticise the NWRL given many of the decisions have been made for political rather than operational reasons. The desire to separate it from Cityrail is to weaken the role transport unions will have in running it. Rightly or wrongly the current government believes all the problems with Cityrail are down to the staff.” – Jim
“I would include the entire decision to build the line as one being made for political rather than operational reasons.” – Simon
The decision to build the NWRL as an independent line, to be operated privately, does appear to be an ideological one based on the belief that the transport union is at least partly to blame for Cityrail’s high operating costs. Jeff Kennett’s Liberal government in Victoria took such an approach when it eliminated guards from its trains in the 1990s. However, while these decisions were political, they most definitely do have operational impacts, ones which in the Victorian case resulted in an improvement rather than deterioration to the transport system. This is not necessarily a bad thing.
Widening the stairs and/or doors
“There is no reason that stairs should restrict the access to and from the decks – the trains are about 3 metres wide, and half this could be stairs from top deck with the other half stairs from the lower deck.” – Dudley Horscroft
The problem with widening the stairs, is that it doesn’t eliminate the bottleneck, it only shifts it deeper into the train carriage. The space between seats in the saloons upstairs and downstairs is only wide enough for 1 passenger at a time to approach the stairs, so even if the stairs are wide enough to handle 2 passengers, only 1 will reach it at a time. Removing seats can allow more passengers to reach the stairs, but by getting rid of seats you are eliminating the primary advantage of double deck trains over single deck ones – higher seated capacity.
“Introduction of carriages with 3 wide doors per carriage like the MI09 on the Paris RER line A will significantly reduce dwell times.“ – moonetau
Double deck trains on the Parisian RER system do achieve lower dwell times, allowing them to have headways as low as 2 minutes (compared to Cityrail’s 3 minutes). However, it remains a fact that Paris’ single deck metro trains still have lower headways at 85 seconds.
“Moonetau is right re “Current two door per side double deck rolling stock is half of the problem.” Three doors would be better, but inserting an extra door in the middle of a car would be rather difficult to say the least. Better to add an extra wide door at each end of the car where there would be less of a problem, the floor is already at platform height. This would give 32 doors per 4 car set, 30 if it is not possible to fit in an extra door adjacent to the driver’s compartment. Together with improved internal stairs this should markedly reduce dwell time.” – Dudley Horscroft
Similarly as with stairs, widening doors would not decrease dwell times as they are not the bottleneck. Wider doors with single deck trains, however, would see a drop in dwell times.
Global economic arc
“What bothers me about running this line as a metro is that is it connecting the least densely populated suburbs of Sydney with the ‘global arc’.
It is servicing semi-rural suburban areas and ignoring the most densely populated suburbs. That’s what metros should be doing; servicing high density areas and doing so quickly.” – Thought
“The fact that that there may be significant numbers alighting /boarding at global arc stations does not really matter as they will never reach the number of transfers TH and Wynyard (must be nearly 40,000 per hour in the am peak) and will not influence dwell times.” – moonetau
There is much uncertainty about this. Take, for example, the fact that more resident of North West Sydney work in the Global Economic Arc (7.7%) than in the CBD (7.3%), or that places like Macquarie Park are forecast to see a high rate of jobs growth in coming decades. While Northwest Sydney is mostly low density suburbia, the areas around the corridor of the NWRL are not, and will only get more dense once the line is up and running.
It might be that these stations North of the Harbour do not get the sort of passenger turnover that the CBD does. But they will certainly have a similar or higher level of turnover as other inner-city stations on the network. Given single deck metros are more suited to high turnover style patronage, that is why the NWRL would still work as a metro despite it’s long distance.
“How would one from Parramatta or Burwood or Mascot get to Macquarie Park easily? They can’t.
A similar proportion of residents in the Hills work in Parramatta as they do in Sydney for example. Who has encountered the traffic streaming down Windsor and Old Windsor Roads?” – Thought
“We are still basing transport planning on getting in and out of the city when the majority of journeys are across the suburban area. Many people from the Hills area work in Parramatta to Penrith and many people who work in the Hills come from the western suburbs. They are ignored by the city centric planners.” – Jim
These are valid concerns, but have little or nothing to do with the type of line that the NWRL should be. Whether it is single deck or double deck, it still will not serve the sorts of connections listed above.
However, in the defence of the NWRL, traffic on the M2 is much worse than the Old Windsor or Windsor Rd in my experience. So if tackling congestion is the top criteria, then a Hills to Macquarie Park link is more important than a Hills to Parramatta link (which does currently exist in the form of the Northwest T-Way). Additionally, the NWRL appears to have been criticised simultaneously in parts for both not connecting to the CBD (despite connecting North Shore trains set to arrive every 3 minutes in peak hour) and for being CBD centric (despite linking up the Northwest with the Global Economic Arc, which employs more residents of Northwest Sydney than the CBD does).