Re: Locomotive /lead or trailing truck puzzle - Definitive Answer?

The collar on the journal combines with a machined face on the journal brass to control lateral movement within the truck frame. In a car truck, the wheel set pretty much floats back and forth and only comes into contact with the brass when entering and exiting a curve, and only bears against the brass until the truck swivels to accommodate the curve. To that end the actual surface that forms the lateral limit is small - the actual face of the journal brass, and the inside face of the collar

On a pilot truck, the lateral control is created by machined surface on either the front or back of the wheel. In some cases a renewable piece is welded onto the face to act as the "hub liner" or wear plate. The truck frame has either babbitt poured on the face or a renewable plate attached to the truck frame with babbitt applied it it and machined down to create the desired lateral motion. There is a lot of lateral force applied to a pilot truck as it literally guides the locomotive into and out of the curves, so a lot of surface is needed to spread this lateral load against the truck frame.

If the lateral force was applied to the small hub on the end of the journal and the small end of the brass, both would rapidly wear out.

The same sort of things happen to the trailer truck and its wheel set/journal box.

I do not think the wheel set is from a locomotive, not with the collar on the end of the journal.