Insert obligatory disclaimer about Screamscape below (I happen to enjoy Screamscape by the way).
(Screamscape hasn't got anything right since yada, yada, yada...)
With that out of the way, here is what Screamscape thinks is happening:
(2/29/12) Lets talk a bit more about that Hogwarts Express project today. According to Screamscape sources the transportation ride hardware may be provided by Doppelmayr, (
http://www.doppelmayr.com/index.php?id=100&L=3) who recently created the Ocean Express themed funicular transportation system for Ocean Park in Hong Kong that travels through a 1.3 Kilometer long tunnel and through the use of a two train system, it can transport up to 5000 passengers an hour in each direction. Also of interest here is the fact that the inside of these trains were wired up with fake video screens pretending to be glass-ceiling panels for an undersea voyage. Sounds a little familiar?
While the Hogwarts Express wont be a Funicular going up a hill, or even through a tunnel, the company does also make a series of regular cable powered shuttles that transport riders on aerial tramways. You’ll find a few of these in Las Vegas or various airports around the world. Now, the insides of these cable cars will be an entirely different matter, and will appear more like the inside of what I believe is called a “sleeper car”. (Forgive me if I’ve used the wrong term… I’m not train person.) The interior will feature a narrow walkway down one side of the car, with individual doors leading into the separate rooms, each furnished with a pair of face-to-face seating bench seats, with a single large window (ie: video screen) to the outside world on the far wall end. This will be your window into the Wizarding World for the duration of your journey between London and Hogsmeade.
5000 passengers an hour in each direction with just two trains is pretty amazing.