John, you're right about the Lionel Train Master. The center bearings are close to the outboard ends of the trucks. But that means that there is a hope that the Williams version would clear--if they were clever enough to move those pivots to the other end of those rather long trucks.
I run the Lionel locomotive on O27, but with several modifications: The most drastic is the removal of the fuel tank, so that the body swings over the switch machines instead of hitting them. I also rotated the pickup assemblies 180 degrees, to get the rollers closer to the middle axle, which has flanged wheels. Otherwise, the swingout of the blind wheels makes the roller short out on the O27 turnouts. I also enlarged the keyholes for the center bearings to allow the trucks to pivot through a slightly greater angle and trimmed a little off the field coil bobbins for the same purpose.
Indeed, the 2383 has no problem at all with O27, because of the vertical-motor geometry. I run mine with a couple of 2243C B units, which are a perfect match for the 2383's black trucks. That's supposed to be the way that Santa Fe did it, with the A and B units bolted, not coupled, together. You had to pay extra for couplers.