"Primitive shoulder belts were an option; these folded into roof clips but did not adjust automatically and needed to be attached in a separate movement after the waist-belt was snapped in, and then restricted movement once in place. The bolts for these belts were added to each car, whether they were ordered or not, so they could be retrofitted later. Center-seat belts were optional, but again the bolts were put into each car so they could be retrofitted."
