TT with a Ruckstell, it would climb straight up a wall in low, low. Bricks didn't matter.
I've hauled my full bed, stacked to the window. Slow on hills, but otherwise, no problems !
Don't know if the brakes on the TT were better then the car. With that load going up a slope, I would want an open cab for easy exit too! Hope he had a full tank of gas.
I'd imagine the tranny brake on a TT works considerably better than on a T due to the low gear ratio worm and ring gears in the rear end. TT's also have a much better parking brake than a normal T.
The transmission brake on a TT is identical to the one on a regular T. The low ratio rear end produces less speed so when the truck is empty I guess it works OK, but with a load like the one pictured I believe the weight would be the determining factor as to effectiveness.
The parking/emergency brake drums and shoes are larger so there's more contact surface.