Dr. Know: The Trains Among Us

I saw a local-access TV show recently about the streetcar to Lake Oswego, and they mentioned NYC's trains. The politician replies: "That's a subway; this is light rail." What's the difference? Isn't everything on tracks pretty much the same?

—Thomas

I've always suspected the readers of this column and the viewers of public-access cable TV are, by and large, the same people. Your further interest in rail transit underscores the clear takeaway: Some folks can't resist a train wreck, no matter what form it comes in.

Speaking of train wrecks, can I just take a moment to register my displeasure at the reinsertion of Ayn Rand (through her No. 1 fan, Paul Ryan) into the national dialogue?

Rand, for those who don't know, was a 20th-century philosopher of selfishness who spent most of her life trying to turn "being an asshole" into something a person could major in. Ryan says he's since rejected Rand due to her "atheist philosophy," which is roughly equivalent to breaking with Hitler over the fact he was a vegetarian. Ugh.

But whatever; you wanted to know about the streetcar. The defining difference between light rail and the various types of rail (including subways) that compose "rapid transit" is that light rail shares right-of-way with cars, bikes, people, etc.

Thus, light rail runs, at least some of the time, on the same streets you and I drive on—you can even hit one! This model saves a considerable amount in initial construction costs, though it means a light-rail system is slower and still subject to the vagaries of traffic.

Subways and other forms of heavy-rail transit, by contrast, run exclusively through dedicated corridors and tunnels. Rear-ending one of these requires an effort outside the scope of normal human stupidity—though, obviously, never say never!

WWeek 2015