CNN

Candy Crowley is aboard the Obama Express.

ABOARD THE OBAMA EXPRESS (CNN) - Rolling into Maryland now with Joe Biden aboard through mostly rural- and lower-income areas. There are clusters of people here and there.

The most striking are the lone people, standing precariously on a hillside just feet from the tracks, waving as the train comes and after it passes: a single woman outside her mobile home waving a giant flag almost bigger than she is; two men standing on top of an 18-wheeler's trailer, hardly dressed for the weather, hands in pockets as we pass; and the man who came out on his back porch, hundreds of yards away from the track, to wave.