The Hiawatha Trail - LRT
Another example of how well rails-with-trails can work is the Hiawatha Light Rail Line in Minneapolis.
The trail is part of the The Hiawatha Line, an 11 mile light rail corridor that runs from Downtown Minneapolis to the Mall of America. It includes stops at the Minneapolis/St. Paul International Airport. The Hiawatha had over 10 million rides in 2008 with 30,500 per weekday.
The Hiawatha was opened in 2004 and the trail stretches from 11th Ave to 28th Street connecting the Midtown Greenway to downtown Minneapolis Between 1800 and 2100 people use the trail per day.
The trail is owned by Metro Transit. Here are some shots along the corridor:
Here's a random video of a couple of guys riding beside the train, clearly paying little attention to the fact they are less than 10 feet from the tracks. Come to think of it, why should they?