That's twice as many times that you have a vehicle needing to slow down, stop, open doors, close doors, and get back up to speed in order to flow the same number of passengers. What's going to be faster (extreme case), one train that makes one stop and lets ten passengers off, or ten trains that each need to make one stop in order to let one passenger off?
No? Each individual vehicle will slow down, stop, open doors, close doors, and get back up to speed the exact same amount of times as if there were 2 or 3 times less vehicles. If we for instance took the Yonge Line and halved the train length and doubled the frequency, a passenger travelling from Finch to Union off peak would still ride the train for 25 minutes and stop at 15 stations. This doesn't change no matter how long the train is, or how close the next or previous train is, assuming everything is properly signaled. Sure the amount of cumulative stop cycles increases with high frequencies, but so what? Is there a concern that we're releasing too much break dust? Do we have some weird power problem where we don't have enough power to account for the extra power needed to counter the... uh... the increased cumulative air resistance of all trains?
And even using your example of passenger behaviour with the doors closing, the counter scenario is that with twice as many trains pulling out of the stations you're twice as likely to have a passenger trying to catch the train. People are dumb. They'll grab the door on the streetcar when there's another one literally directly behind it.
Again, you're looking at data cumulatively, and are arriving at data that is basically meaningless. Don't look at "how many times someone holds the doors open within a timeframe?", look at "what is the chance any particular train will be stopped at a station by someone holding the door, and how often would it happen in any continuous end to end journey?". If we take a pessimistic value, and say that when a train stops at a station, there's a 50% chance someone will hold the door open. Sure, if you have trains arriving at the station twice as often, then sure you're going to have a train delayed twice as often, but so what? Your average journey will still experience the same delays. What matters is that 50%, does that number go up or down as frequency increases, and it usually goes down. Sure, idiots will still try to hold the door open, but the chance that someone would want to do that goes down as the headways decrease, or at the very least, it certainly doesn't go up.
Again, I'm not disagreeing that a larger number of smaller vehicles may offer advantages in some scenarios, I just don't think it's correct to assume that halving the size and doubling the frequency will necessarily work out to the same thing, in all cases.
Correct, there are differences, however most of the actually meaningful differences do not apply here. A simple example is express services. Say you have a 2 track mainline, with passing loops at specific stations, and you want to create a skip stop service. The less frequent your trains are, the more room you have to run these express skip stop services. Lower headways means there is a much larger distance that your express trains can cover before they begin to tail the train in front of them and they need to hit a passing loop, so if you want to have more express services, then it makes sense to run longer trains at longer headways. Obviously however, none of this applies to the subway lines we're building.
The second difference is future expansion. If you build your system with longer platforms, but make it capable to run at higher frequencies in the future, increasing headways is always going to be an easier solution to increasing capacity, than increasing train and platform lengths. This is arguably the only real point the Crosstown has in its favour, if in the future we fully grade separate the line, we can run frequencies approaching 90s and massively increase capacity. However the real solution here is to design your station with expansion in mind, keeping the tunnels approaching the station as straight and flat as possible. Not to mention, people on here seem convinced that Eglinton will NEVER need more than 15kpphpd so
. This also further puts into question the choice of Low Floor vehicles. As the person you responded to said, the line should've been built with high floor trains, since if and when in the future the change to full grade separation happens, the low floor trains will be nothing but a detriment to the line and the service it will be trying to provide.
