RT @levydr This app could be seriously useful for WMATA, too. http://is.gd/14qTz Should be distributed to all tourists and hill interns.

Via a tweet by @unsuckdcmetro (and you can follow me, if you want, [shamelessplug]@malnurturedsnay[/shamelessplug]), I learned of a cool application for the iPhone, which allows users to determine which car on the London Underground to travel on in order to be positioned quickly to their destination station’s exits:

TubeExits is for the serious tube rider. It tells you specifically what carriage to board to make sure you arrive directly opposite the relevant exit on your journey.

I know Liverpool Street — Tottenham Court Road. I know those exits. I know where to board and exit. But any other tube station in London? No.

@unsuckdcmetro commented: “This app could be seriously useful for WMATA, too.”

And I completely agree — but I have a caveat, and it is this: I have no idea how many cars the London trains run. I do know that Metro runs six and eight car trains, so the concept of telling them which car to be on is impractical, as the third car on an eight-car train will arrive on the platform in a different position than that of a six-car train. This assumes, of course, that the train is stopped properly (Metro runs 4-car trains? Really?).

So, obviously, the answer is to tell someone where on the platform to stand.

For example, I travel from Woodley Park to Grosvenor. I know that if I descend the escalator, and reverse myself once on the platform, that if I walk to the first pillar past the first bench I come to, that if I board the front of the car that stops right there, I will emerge from the train directly at the foot of the escalators at Grosvenor.

Obviously, this will never be perfect for a system that uses multiple-lengths cars, particularly when your destination are stations like Tenleytown or Farragut North, which have either escalator or elevators directly in the platform-ending walls. A direction to ‘stand at the very last bench at Grosvenor to emerge at the northern exit from Farragut North’ is going to be problematic if it’s a six-car train arriving on the platform.

Oh, and also? I don’t have an iPhone.