Steel thickness: lockers tend to be made from a standard thickness of steel, which is commonly 0.8 mm. thick; but heavy-duty or high-security lockers are offered as a standard option by some manufacturers, or may be available on special order. A typical locker of this sort may be constructed from steel 1.2 mm. thick, for example, and is usually fitted with three-point locking, regardless of the number of tiers.
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.