I've often wondered about the upcoming lengthening of the 1996TS to 7 cars and how it will affect dwell times compared to 6 car trains.
On the one hand, you can get more people into a 7 car train, thus providing for more platform-to-train movement and preventing long dwell times due to lack of entry space. On the other hand, since you have more space for people, more people will try to get on and thus hold the train in the platform even longer than usual.
What kind of research has been done on this topic?
I very much doubt that more people will turn up for a train simply because it has 7 cars not 6. The extra capacity surely is for future growth and until that hapens dwell time will be shorter.
I don't think it is for future growth. Ever tried getting on a Westbound at Canary Wharf between 17:30 & 18:30? One car extra isn't enough now- by the time the new signalling system comes along (2009) things will be really bad. More towers due, I understand.
From what little I have read in that field, train length is not so much an issue, as long as it is within reasonable parameters (i e, not something ridiculous like a four-car train in the peak on the jubilee).
What matters is flow and throughput, meaning that a large number of doors, with interior and exterior desing facilitating rapid movement of passengers, both deeper into the train, and along the platform, gives generally shorter dwellign times. See, for example, the queing lines painted on platforms in several places around the world, showing passengers where to stand on the platform to end up next to a set of doors, and not stand in the way of disembarkign passengers.
Passengers are a bit like data packets, actually. They don't care how long the cable is or how big the train is, as long as they can quickly get through a door or router.
You know I cannot understand why the Jubilee is restricted to 6/7 cars. All the platforms north of Baker are 8 cars long. (Not sure about the extension) so why not make the trains 8 car length?
Then they get 8 and someone will enquire "Why not 9."
They do cost money, the extension was only built for 7 and the line is extremely lucky to be invested in again so soon after it last took all the money. If it hadn't been for the Central and Jubilee, London may not now be scrambling to get a decent tube running in time for 2012.
Sorry, didn't mean for that to turn into a rant, but it's true ;D