A few years ago Bachmann acquired the line from Williams and made a few changes. They've upgraded the sound, introduced a few new models and paint schemes...they've also upgraded the price. I haven't purchased any of the Williams-by-Bachmann trains (yet), so I can't opine on this new generation.
Here's a Williams GP-38 I acquired second-hand at a meet a number of years ago:

Extremely powerful with its dual motors, I don't have enough freight cars on the shelf to slow this thing down. If I ever get around to trying my hand at weathering a piece, this might be the one.
Paul II