Vancouver's Skytrain network - a model for Melbourne's future rail lines

Vancouver's SkyTrain started out as an expo line back in the 1980s and has now morphed into three major lines with a fourth on the way.  If you have a spare 30 minutes, I recommended watching this suavo 1985 documentary produced by the operator of the Skytrain Network, BC Transit,  titled "Going to Town" - despite the huge clunky-keyed keyboards, 1980s haircuts and retro livery schemes, it provides a brilliant insight into how automated train networks operate.

The Canada Line is the latest (not including the under construction Evergreen Line) to be open for passengers.  It was built for the Vancouver 2010 Winter Olympics as a mass-transit option for Vancouver's southern suburbs as well as an airport link to YVR airport.  It's automated like the Millenium/Expo lines, but the trains themselves are conventional in the sense they do not use linear induction motors and the "4th" rail like the Expo/Millenium lines do - the line effectively operates the same kind of service and can operate in the same way (i.e flick of a switch, trains can be added into the network to meet acute demand when and where necessary) with the same fares applying network wide.

The purpose of the article is to familiarise people with driverless rail technology - it's not a big scary unknown that would require 10 government studies even before a proper planning process kicks off.  The same principles of rail planning apply: ruling gradients, distances between the train and platform are uniform, disability access is encapsulated throughout both vehicle and station design etc.  The railway itself looks very much like a conventional line with a few minor nuances:

• the lack of line-side signalling, this is because there's no driver's to look at them!  The smarts of the system are remotely controlled.
• the platforms are shorter than what we're used to, that's because the system is capable of extremely high frequencies thus not requiring longer trains.  The lines are built for higher-than-Metro-Melbourne train frequencies from day one - the lines simply use smaller vehicles.  Scalability becomes a project of extending platforms (if they're not already built for future expansion in the initial build) and ordering more vehicles to operate longer trains.
• there's a mixture of underground, at grade and elevated track. Vancouver has effectively built this system from the ground up and the city didn't have a history similar to Melbourne's where we grew along the rail lines that spiralled out of the core of the city.
  • This marked difference is in fact actually a national difference between Australia and Canada - Australia's early railways, like Canada's, were private monopolies, but Australia's were nationalised very early on and it became the government's job to expand the rail networks where much of the Canadian high capacity mass transit networks in Vancouver, Toronto & Montréal were built from the 1950s onwards.  
  • In general terms, Toronto's subway, Montréal's metro and Vancouver's skytrain are limited to inner areas and do not have the same metropolitan-wide scope Australian city rail networks do: Melbourne has the arteries, it's now time to connect them outside the inner city.

Comparitively speaking, even without doing a government study it is, on paper, highly plausible that such a line, or system of lines to expand and link existing conventional lines outside the inner city, could be implemented in Melbourne for a lower capital outlay; why?

• The standard platform length for new lines (Rowville Rail Study) utilising the existing fleet will be 250 metres so 9 carraige trainsets can be run (Melbourne Metro Tunnel is mooted to be built with this standard) - Canada line trains are 2 married motor cars measuring 41 metres in total length, thus the platforms in each of the stations are under 50metres in length.  As a rule of thumb should such a system be built in Melbourne, stations with 100m platforms would provide scalable capacity to fit 4-5 car trains.  Shorter platforms whether they are at grade, underground or elevated = reduced station construction costs.   
• The 2 carriage Canada Line trains have a standard seating+standing capacity of 330 people, "crush" capacity is 400 per 2 carragie train. A Comeng, X'Trapolis or Siemens that currently roam the Melbourne network have crush capacities around the 800 mark for a 6 carraige train.  
• The key point is that the Canada Line will, and does, operate on more than double the frequencies of any single train line in Melbourne - thus providing the same level of service, but in a way that is more attractive to the travelling public: frequency of service.  The number of seats in a train should never be the main attraction, it should be how frequently the train comes and how quickly it can get you to your destination. Whether it's travelling longer distances or getting you to a connection - this is heavy rail's role in an urban transport network: high frequency, high capacity and high speed trunk routes with the "last mile" work taken care of by road-based public transport options if the passenger does not live, work or shop near the train station.
• The trains have a smaller profile (dimensions - and don't require overhead catenary as they're powered by 3rd rail) and this translates into smaller infrastructure profile requirements: tunnel diameters are smaller, clearances above the train's roof is not as high (for overhead bridges).  Smaller infrastructure requirements therefore translates into, on paper, lower capital expenditure requirements.  Any new lines in Melbourne will require underground components; it's a fact of life, no government or authority wants to create more level crossings in a city that already has way too many of them - elevated and underground sections must be part of the solution, not part of the backlash.  
• Using a Tunnel Boring Method of constrution, the Canada Line (or a solution like it built to the same standard in Melbourne) yields a 12-15% reduction in tunnel diameter as compared to the existing City Loop tunnels.  Canada Line had a 6.1m Tunnel Boring Machine dig the TBM components (internal diameter is 5.3m), source.  City Loop: external diameter 7m, internal diameter 6m (sources vary).
• Cut and cover tunnelling: Canada Line 4.26m high and 4.6m wide and are built either side by side or stacked on top of one another.  An X'Trapolis class train has a height of 4.2m + requirements for more space to fit catenary above the trains.
• The slimmer profile (and therefore weight) of the trains also means if a cut-and-cover method of construction is selected for a segment of rail line, you can innovate considerably by double stacking the 2 tracks below the surface in a wide road median - minimising distruption during construction to road traffic as well as nearby houses and businesses.  This is especially relevant to Melbourne given roads like Warrigal Road, Station St (Box Hill), Wellington/North Roads, Bell St, Melrose Drive (Tullamarine), pre-redevelopment Fisherman's Bend could all have the road space temporarily reduced whilst work is underway.  

Example of cut-and-cover construction employed in Vancouver.

In a conventional train line system with conventional line-signalling, the signals themselves are sign posts, among other things, for the start and end point of a fixed block - this separates trains and stops them from running into each other.  For example on any train line in Melbourne currently, a train you may be travelling on will traverse several fixed blocks deliniated by a signal and the signal tells the driver if it is safe to move into the next block and also tells the driver at which speed they should proceed through to the next block.  Vancouver's Skytrains are themselves a moving block - as the train moves forward, so does the block, thus maintaining separation and tells trains that are behind to either speed up or slow down depending on how close the trains are together - this is all handled automatically with oversight in a centralised control room.

It's this moving block concept which allows the Vancouver skytrains to run at incredibly high frequencies - on the Millenium/Expo lines the theoretical min separation of trains is 75 seconds.  Small trains, very large capacity.  Currently you will only see frequencies of 2-3 minutes on the Burnley or Northern City Loop tunnels - this can be upgraded (and should to squeeze as much capacity out of the existing network as possible).

Some of the recently released Rail studies into Tullamarine, Rowville and Doncaster all assume convention trains will run on these lines and have purported to gold-plate everything making the proposals appear overbuilt, unnecessary and above all else costly giving any government of the day a free kick to place the projects in the too hard basket.  There are cheaper to build, practically off-the-shelf, solutions available worldwide with the same company that built Vancouver's first skytrain line having a large presence and therefore transferable knowledge pool, in Melbourne.

The set of photos below were taken on the opening day of the Canada Line back in 2009 - photographer is Ian Ius on the SkyscraperPage forum and they are being republished here with permission.