Excellent - thanks for the quick reply!

Is the motor in an O27 Hudson (6 wheel drive) interchangeable with the motors in a Bershire/Class J?  I know the Lionel Postwar and/or MPC-era version would not be - although both locos utilize the same basic shell casting, the small Hudson had a frame-mounted motor and the Berk/Class J/Turbine all utilized a worm-gear drive - but I was wondering if the Williams O27 Hudson uses a worm drive like the Berk/Class J/Turbine.

The reason for my question is that I'm considering swapping the 8-wheel drive (and 4 wheel trailing truck for that matter) with a 6-wheel drive (and 2 wheel trailing truck) on my B&O Congressional "Class J" in order to make it a "Pacific"/4-6-2 (like the prototype B&O locos were) as opposed to a "Northern"/4-8-4.