The plastic draft-gear box covers are also secured with screws. The Rapido HO scale mechanical refrigerator car uses Kadee No. 5-style metal knuckle couplers with No. 634-style centering springs.

The information you'll be most interested in for your HO scale Tyco cars is on page 81. In the middle column, they discuss how to replace truck-mounted couplers with body-mounted couplers.