Abstract: A repositionable thermal barrier for truck trailers has a hanger bar extending across the width of the trailer with a flexible strip-type or blanket-type thermal insulator supported by the hanger bar. A trolley-and-hinge assembly attached to one end of the hanger bar is repositionable along a trolley rail attached to one interior wall of the trailer, and a releasable latch assembly, attached to the remaining end of the hanger bar, is selectively latchable to a latch rail attached to the opposite interior wall of the trailer. A trolley lock engages and disengages responsive to the pivotal movement of the hanger bar to allow the tolley to move along the trolley rail.