The invention that made the production of clothing more efficient in the 19th century is the sewing machine. The sewing machine automated and sped up the process of stitching fabric together, significantly increasing the efficiency of garment production compared to hand sewing.
The cotton gin also played a role in the clothing industry by making the separation of cotton fibers from seeds faster and more efficient, which in turn increased the supply of cotton for textile production.
The steam locomotive and mechanical reaper, while significant inventions in their own right, were not directly focused on clothing production. The steam locomotive improved transportation, and the mechanical reaper increased agricultural efficiency.