Gordon , some engines "nose around" more violently than others . 470s seemed to track the best , handling even rough track with a minimum of shaking or "nosing around" ,though ,like any engine they will let you know when you are going a little too fast on bad track . Though the 463 could jump around a little , because of its short wheelbase ,it also tracked very well . God bless those 480s ,they are the best locomotives in the world ! Tough ,powerful ,like a Chevy ,you can really expect a lot from these strong , durable engines . But ohmygosh , they are hard riders . Even on a low spot or kink on straight track , they will nose around violently , trying to shake you off the seat ! And yes ,it scares the snot out of an engineer . They REALLY do not like bad track ,and are happy to tell you .That they used 480s on the "San Juan" passenger is mildly surprising , since they do not like speeds over 15 mph very much . A couple of factors may be to fault . The 480s have a very stiff trailing truck . To compensate ,mechanics allow a lot of slop on the number one driver (especially on the D&SNG , because of tight curves) ,and that also will cause an engine to "nose around " or "hunt". Finally , if the flanges on the number one driver are real worn out ,that will cause an engine to "hunt" and nose around at speeds of over 15 mph . Curiously ,though 497 was notoriously rough on track (it liked to kick out curves) it was a reasonably good rider .