Also I would NOT recommend double level EMUs for ST. Proof has shown that they are definitely not worth the investment. The best example of this is in Australia. Sydney and Melbourne have similar suburban systems that travel out from the downtowns with many more stops than commuter rail and both systems use catenary trains. The difference is that Sydney uses bi-levels and Melbourne standard Metro cars.
Due to the relatively short distances between station, Melbourne's system is faster and more reliable because the trains are far aster to un/load while Sydney's take much longer due to 2 levels and thus fewer doors as well as stairs to negotiate and slow access for wheelchairs. The dwell times on the Sydney system are considerable longer making the trains slower and less reliable.
ST will have a lot of on/off traffic at all stations unlike the current GO where basically everyone gets on/off at Union......there are no stations where there are people getting on or off. With more suburban systems like ST one level trains are the way to go and Sydney is now ordering one-level cars like Melbourne's to speed the system along. Melbourne use to use bi-level trains but got rid of them ages ago and only now has Sydney caught on.
The interesting thing is that Melbourne's system actually has higher capacity than Sydney's despite only using one level trains because the dwell times are far less, the trains are more reliable, and the have much higher frequency capacity.
It's slightly more complex. Sydney's trains: current metropolitan network, the inter-urban and inter-city network will remain double-deck for a long-while yet, the New South Wales government just ordered a complete replacement (double deck for double deck) of their inter-urban and inter-city fleet.
The single deck trains that they've also ordered is for a dedicated, operationally-independent rail line that's not going to mix with the current rail network (like how you guys would differentiate subway with current GO service - they may both run on the same track gauge, but they're completely independent networks).
Sydney's rail network is already highly-sectorised (meaning different lines/groups have their own dedicated tracks in most parts of the system), the new metro line doubles as a radial commuter line from an area of outer Sydney which doesn't have a rail service at present and links multiple employment centres en-route - it's also going to see conversion of one of the existing rail lines (and therefore, as it'll be taken out of the existing network, it creates more space on the existing network). This line will be fully automated/turn-key type system ala Skytrain in Vancouver, just with relatively long trains (6 x ~20m if I'm not mistaken).
Here in Melbourne, the network is not really all that sectorised, save for the 4 groups which generally have 3-5 lines in each since the City Loop was built in the 70s/80s. The Melbourne Metro Rail project is the first project that will see lines from two different groups taken out of the current setup, merged and completely sectorised and in many ways orphaned from the existing network. A new dedicated train fleet that, after platform extensions, will be able to handle up to 10 x 22-23m car trains (we currently use 6 x 22-23m: basically about the same length as a TTC train at present), and rumoured to have different power voltages (1500v DC -> 3000v DC), and will have a new control/signalling system that will be able to have human operators or in future switch to automated (the tender for the new trains stipulated this sometime-in-the-future switch ability needs to be in the respective proposals).
The new Sydney Metro line will be single deck, but there's still a bit of track space to be squeezed out of the lines that have double-deck fleets because they're still on a standard block signalling system - shifting to moving block will probably yield a bit more capacity.
As to whether Toronto should have singles or doubles on this new train line, the thought process should be something like:
- will the train service have exclusive access to track and platforms along the entire route? If yes - positive for cheaper single deck trains. If no - less positive for single deck trains, more positive for double deck, especially if capacity is going to be constrained (i.e services will be mixing with freight trains or inter-city trains).
- what's the longest conceivable commute time? If over one hour for terminus to centre of the city, more positive for double deck trains, if less than one hour, more positive for single deck
- assuming services will have exclusive track access (i.e they can significantly scale frequency to meet demand [assuming they have the train sets]), how quickly could patronage rise due to denser development at stations / the network effect of making the centre of the city/other employment nodes quicker to access from farther flung areas of the metro?
If it's quite possible that patronage could grow fast, it's a 50/50 single or double deck choice in this instance: exclusive access to track/platforms means that either infrastructure can be expanded relatively easily/cheaply (for longer single deck trains as its needed over time with little disruption cost to other rail services) or just bite bullet from outset and procure more expensive double-deck trains from the start and just add frequencies as needed.
If it's not likely that patronage growth will explode: keep it simple/cheaper with single deck trains.
-- another point to keep in mind: train fleets generally get refreshed every 30 or so years: first generation could be single and if warranted the second generation could go double eventually. Plus there's nothing really stopping having a mixed fleet - from the outset or over time - if demand profiles will different on the line will be dramatically different (i.e double decks run from the outer suburbs, single decks run shorter services boosting capacity in areas where they're greater demand/patronage).
My opinion on platform height: high platform all the way - it keeps things simple (train procurement, faster boarding/disembark because people aren't "climbing" on to the train, far more accessible).
$0.02 / HTH.
