Double Truss AAR 50-Ton Trucks
with insulated metal RP-25 contour wheelsets.
“Self-Aligning Spring-Plankless 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.