Doug Cockerham Died several years ago. All his work was for contract speciific
for his customers and the model he was working on. There are nor drives available for sale that I know of.
He would install them in the Crappy drives that overland models had in most all the big O scale UP models. They were garbage IMO.
Sadly, Doug died a couple of years ago. I have several articulated steam locomotives that he rebuilt for me, one of which he completed and returned to me only a few months before his death. Not only did he rebuild the drive train with a large Pittman ball-bearing motor, ball-bearing gear tower, and ball-bearing NWSL gearboxes, he gave my old Max Gray Rio Grande L-132 a beautiful paint job. Doug's work on diesel models typically incorporated the large Pittman motor, a central gear tower transmission, and drive shafts with excellent machined universal joints powering Overland gear boxes.
he always had this thing for large motors with reduction gearheads, iheard they were noisy
I know of a number of O scalers here in the east who have had Stu Klienschmidt[may not be spelled correctly] do drives on there older O scale imports, I believe he was in the Chicago area. I do not know if he is still in business.
I had a bit of gear whine in one of Doug's steam engine conversions, but lubrication of the gear train in the transmission to the lower drive shaft helped with that. Strangely, the noise is at low speeds only; at normal running speeds, all the engines that he rebuilt for me run very quietly.
My big MG Rio Grande L-132 (a 2-8-8-2) draws less than 0.50 amp at around 10.5 volts pulling 30 free-rolling cars at a stately speed. Also, it will creep along very, very slowly without hesitation, when necessary, as will a USH L-105 that Doug rebuilt and painted about 10 years ago.
I agree that the quietness and simplicity of a toothed-belt design has a lot to recommend it. So far, however, Doug's drives have been "bullet proof" in my experience.
If push comes to shove there is always the conversion drive done by the guy behind Midwest Model Works. I have read that his drive is very well thought of, quiet, powerful, and very low power draw. Check the pictures on the site. The work is beautifully done.
With all the options this is a 1200.00 drive[755.00 min for 6 axel diesel] a serious upgrade for your favorite diesel.
i believe Stu Kleinschmidt is still doing drives. i have a custom brass Milw BiPolar that he did as well as a gem PRR F3 2 6 0 a Milwaukee Atlantic as well as a PRR streamlined K4. they are all excellent runners and super quiet. as far as i'm concerned money well spent. my bipolar couldn't pull itself now there's not much it can't pull. his drives Jerry White and Chuck Strayer did some amazing stuff when it comes to powerful stuff.