Lockers are usually physically joined together side by side in banks, and are commonly made from steel, although wood, laminate, and plastic are other materials sometimes found. Steel lockers which are banked together share side walls, and are constructed by starting with a complete locker; further lockers may then be adding by constructing the floor, roof, rear wall, door, and just one extra side wall, the existing side wall of the previous locker serving as the other side wall of the new one. The walls, floors, and roof of lockers may be either riveted together (the more traditional method) or, more recently, welded together.
There is a luggage storage service a short one minute walk from Union Station in downtown Denver - LUGDEN. You can make a reservation online - lugden.com, call - (303) 747-5600, or show up as a walk-in. They offer hourly, day, overnight and weekly bag storage. Great place to store your luggage if you're on a layover from Denver International Airport, or going to a concert, or headed to a Rockies game at Coors field and want to enjoy yourself without having to lug your bags around.