Yep. Those are twin frame rail trailers. Up in northern Alberta they've started using "spine" trailers in tri-tri-tri setup. Spine trailers just have a single rail down the middle. Not sure what they tare in at compared to the twin frame rail ones.
Regular super b are getting a lot more common in BC. You can deck the pup on the lead to shorten it up empty. The tri-tri-tri is more an Alberta setup. Pretty flat in most of Alberta.
For Winter driving and pulling a super b you need a tri drive with lockers. Let's just finish it with a CAT & 18 sp.
Hauling super-B loads of rig mats, paid by the mat, drivers on percentage, during spring break up with an early completion bonus on the line. And a scale with no practical way to bypass. Whee... Made for some nervous trips.