33" ribbed back wheels Accurate markings Incredible detail True to prototype Non-magnetic Metal wheels Highly Flexable sprung trucks Metal SideFrames & Bolsters Fully Sprung Smooth tracking Free rolling Contoured Insulated Axes RP-25 Free rolling wheels.The Vulcan truck was introduced in the 1920's as another replacement for the archbar truck. The Vulcan design incorporated a pin which held the journal box in place. Removal of the pin allowed the journal box to be quickly replaced. This truck lasted to the end of the steam era on mainline railroads and somewhat longer on logging railroads.