D&RGW M-68 4-8-4

Research & Resources

Doug's locomotive is not only the first F scale 4-8-4 to be built, but it is also the first F scale two-rail electric, standard gauge steam locomotive to be built of any sort in 1:20.3 (my baby 4-6-2 is a close second, but for now Doug is well in the lead). Elevation and section drawings for this project came from Kalmbach Publishing's Model Railroader Cyclopedia--Volume I: Steam Locomotives, whereas drawings of the distinctive Baldwin disc drivers were found in a late 1930s era Locomotive Cyclopedia. Of additional help has been an HO scale model by Overland Models. Additional prototype drawings of the M-68 may exist, most likely at the Denver Public Library.

Having friends to help on a project as complex a 1:20.3 scale standard gauge 4-8-4 makes all the difference in getting off the ground. In the first place, Doug has had the singular good fortune of a patron, Mr. Gary Bartlow, who commissioned the building of not one but four M-68s. Doug Cockerham, another Texan who is well-known in the world of 2-rail O scale for repowering imported brass locomotives, is machining and assembling the drivers as well as milling the main frames and fitting various other running gear on the latter three locomotives. He will also be testing the units after final assembly. And speaking of drivers, Mr. Bill Brisko of Pacific Locomotive Works provided the rapid prototype wax patterns of the M-68's Baldwin disc drivers based upon his own SolidWorks 3D CAD drawings (for about $2700 if you're interested in that side of the equation). Bill is also responsible for producing 3D CAD drawings of the valve gear, side and main rods. Rino Mechanical Components provided the custom built worm gearboxes (for about $337 a pop). A Pittman 14000 series DC motor powers each locomotive. 73" steel driver tires came from me. Tender, lead and trailing truck wheelsets were from my original stock, now sold by my good friend Don Niday. David Fletcher, a large scale modeler--in Melbourne, Australia--did the initial 2D CAD work for the main frames. Additional help has come from a consortium of modelers residing in the Houston area:  James Engle custom made the D&RGW decals, Ward Hammond laser cut the cabs and the latter three tender's side & end panels, Barry Bogs is installing the electronics on these locomotives, and Jim Srensaki (famous for at one time cornering the market on all available Bachman GE 45 tonners) painted the first cab.

The Tender                                                                                                                          

The Chassis & Drivers                                                                                                               

Immediately above are the Baldwin disc driver centers specific to the M-68 that Bill Brisko produced on a wax stereo-lithography machine from his own SolidWorks 3D CAD drawings. These were themselves based upon a 2D drawing published years ago in a 1940s era Locomotive Cyclopedia article (pictured above). Bill's wax originals were then burnt out to become the actual investment cast production drivers. The machining and fitting of the driver centers to 73" steel driver tyres that I provided is being done by Mr. Doug Cockerham in his shop outside of Houston.

Below are photos of the chassis for the first locomotive at various stages of its construction. The frame for this first locomotives was milled by Doug Hemmeter the hard way--on a desktop Mini-Mill! Frames for locomotives #2-4 were produced by a commercial machine shop in the San Diego, CA area, and then trued up by Doug Cockerham (pictured at left). Each frame is then matched up with a Pittman 14000 series 24 volt DC motor and a custom-made Rino Mechanical worm gearbox (first row, left). A set of brass & delrin universals, from W. M. Berg, complete the drive train.

Boiler & Cab                                                                                                                

Last update: 18 September 2007