This causes all kinds of problems. The fat end passes the thin end, and the que turns. Because train wheel treads are not flat but rather slightly cupped, we recreate this phenomena by changing the contact band so that the wheel on the high rail has a larger rolling but rather slightly cupped, we recreate this phenomena by changing the contact band so that the wheel on the high rail has a larger rolling diameter than the low rail wheel. The sharper the degree of curve, the more pronounced the effect. Thus all the different profile shapes.
Tangents are different.
We create to different contract bands on alternate subdivisions so that we can wear the train wheel treads in a manner that does not allow the tread to become too cupped. They have some interesting articles . Loram's locomotives seem to be almost completely home built, where as Panderol Jackson's are off the shelf units which have had new sheet metal applied. Often some sort of accomodation is included in the train since it may not always be able to end the working day at a location where meals and accomodations are available. I have no record of where Loram is headquartered, maybe someone else can provide that info.