@@alyfer0862 Yes we Americans are very far behind in terms of trains! This isn't even high-speed rail, but at least it's reasonably modern, quick quiet, efficient, etc., up to the basic standard in Europe.
Articulated buses are stored in the North bus yard, and route 40 is one of the routes that use buses stored in that yard. Other routes that use buses from the North yard but do not usually contain articulated buses are: 21, 51, 52 (usually serves 40 throughout the day as well), 53, and 89.