National Hardware 196-360 5020 Box Rail Trucks O

Used it to make a movable hoist in my garage (see pics). I worried it might not fit the Stanley Steel Box Rail from Ace but worked like a charm. Block and tackle are from AMZN and the S hook fits right in the 1/2" swivel. All in all I'm very pleased. Figure I have about 250lb lifting capacity with three 2 1/2" wood screws into the ceiling joists.

Used these to hang a couple of barn doors on my storage shed. They work perfectly and are sturdy enough to hold doors that weight twice as much as the ones I built.

Fit perfectly in National Hardware box rail. Slides smoothly. Hole for bolt/stud/clevis/hook is 1/2".

Use product to top mount barn doors, heavy duty great product.

There are two types of barn door hanging trucks, cars or trolleys. Ones with a straight or fixed shank and ones that swivel at the "T". Consider whether your door will have any horizontal forces ever imposed on the door (such as wind gusts). The swivel mechanism in this truck trolls allows for slight (~15°+) rotation without putting any torque on the wheels or box rails. The door will be able to swing out without ripping the track off the wall or breaking the door. There are two types... if you're considering this for outdoor applications, do not forget to consider mother nature and an errant blustery blow. It's better to give than to recieve (a new costly replacement part from Amazon because you didn't think ahead or know you had to).My $0.02