HO Double-Truss AAR 50-ton Trucks w/semi-scale wheelsets (two trucks)

"Self-Aligning Spring-Plank-less Double Truss Truck" is the full name for this truck design. Introduced in early 1936, it quickly became popular for new freight cars built up into the mid 1940s. The Double Truss feature strengthened the spring seat area allowing room for more springs.