Some do, some don't

Many of the more modern Kato and Atlas locos have smaller flanges, but few are specifically geared to run on code 55 straight from the box.  As you may recall Walthers bought Lifelike some time ago, so if parts were available then they'd be your source.  I don't believe that Walthers retooled the former LL locos.

One approach I've seen used successfully is to locat trucks on a newer locomotive and simple swap the out if the gear tower fits.  Of course, I have also seen people chuck teh wheel sets in a dremel tool and grind down the flanges,

"Some do, some don't"

Thanks for the response. I guess I'll hafta check out new locos and look for one with smaller flanges. Maybe I can file down the GP 20 a bit and see how it works then, I mainly just like it for the low nose old school SP look........DaveBranum

Problem solved

 I pulled off the shell and clamped the frame in my panavice then hooked up power leads and ran it while grinding the flanges down with a dremel disc. A bit of clean up with an emory finger nail board and sand paper and it's close to fitting in the  NMRA gauge wheel notches and doesn't bump over the frogs any more. I wouldn't recommend this approach to the squeamish as there's lots that can go wrong grinding on a tiny drive with a high speed cutting disc. The only mishap I had was sanding a tiny bit of skin off my finger :> ) ...DaveBranum