Well, if you have read my web site www.elmassian.com you would know
that I'm a fan of removing the traction tires from locos.
Main reason on USAT is the split axle problem, where the plastic axle
splits and the wheels spin in the axle "housing". It's a design flaw
that has been around forever.
Each 2 axle motor block has one axle with smooth metal treads, and the
other axle has rubber traction tires on it.
The traction tires definitely give more pulling power, but what
happens is the load is unequally balanced and the traction tire wheels
pull more than their share. So their axles split first. By removing
the traction tires, the load is better balanced between all axles.
Also, if you have a crash, the wheels will spin with no damage, but
when you have traction tires, they dig in and cause more damage.
Finally when you replace the traction tires with "solid tread" wheels,
then you have more power pickup, and you can remove and throw away the
stupid sliders, that short out on some turnouts, and get stuck on some
The only downside of doing this is that the locos cannot pull quite as
much. But, diesels were made to be MU'd so just an excuse to run two
on a consist!
See my site on the USAT locos for more info.