I have been thinking about this mod for some time. I have a few Pullmor NYC Hudsons from the '90s. I also have a K-Line Hudson with the smaller Mabuchi motor and while a fine looking engine I was never impressed with its pulling power. Checking the Pullmor frames it was obvious a Pittman would not be a drop in mod. What finally pushed me to start this project was learning that Lionel is beginning to offer its early legacy boards for sale. In particular was the sound board for the Vision Hudson, cab number 5344. It seemed only appropriate to start with a Commodore Vanderbilt Hudson as it was built on 5344.
I thought it would be a good idea to start with a spare frame to cut up in case any mistakes were made. I don't claim to be a machinist but have the equipment and know how to make chips. As any machinist knows one mistake with a hand wheel and 2 days work and $$$ can go down the drain.
Here is what I started with after removing the electronics. I was hoping that simply removing the motor mount would allow placement of the Pittman.
CV Body Before:
Well I was wrong but this is what I ended up with. (Smoke unit tilt is a lens aberration)
Between the first photo and second these were the mods required. The mounting posts in the body were too close together for the Pittman to fit between. Not only did the posts have to be removed, the fame needed to be widened for the new screw locations and body modified for screw mounts.
Below are the frame mods with attachments for screw mounts, motor mounts, plus fan smoke unit mount.
Modification to the CV Body. Aluminum blocks were attached with JB Weld after the original mounts were machined off. No room for screw holes into the body.
Other minor mods were shortening the worm shaft and resizing from English to metric to match the motor shaft diameter. Also the smoke unit stack to fit the CV. Then adding one of my Lionel Niagara driveshafts. I had tried a shorter driveshaft with a single U Joint but found the angle too steep. The longer double jointed U Joint has less of an angle but required redrilling the frame to allow the motor being moved further back. Another good reason for starting with a spare frame.
Also the flywheel was modified to fit the short shaft and still allow fitting the driveshaft.
While doing this mod I learned a lot about the Pullmor Hudsons and even about the modern Hudsons going back maybe to the 700E. I don't have any pics of a 700E chassis but have seen the the 1950 773 and the chassis from then through the '90s appear to be essentially the same. I can only guess the 700E is also the same given many of the more modern replacement parts still carry its ID number.
While short on detail they were built like tanks with quality parts. They were also built using English dimensions and many parts do not interchange with the later metric Hudsons. I was hoping to replace the plain bearing rods with roller bearing items but wheel spacing went from 1.75" to 44 mm or 1.732". Close but no cigar.
Here is an example of the worm gear from a Pullmor Hudson compared with the one from Lionel's Niagara. The Niagara gear is the small dot in the middle of the brass gear. Any surprise they failed?
Here are the side rods from the CV Hudson (right) next to the siderods from a Niagara. Note the bronze bushing in CV rods
Anyway, other than repainting this pretty much completes the mechanical mods. While tuning the motor and driveshaft placement I used my DC power supply and made adjustments for minimum current draw. Starting at over 1 amp I was able to reduce it to .35 amp at 10 volts.
Next step, installing the Legacy electronics. I was going to add a swinging bell but as its buried in the CV shell its nearly invisible and there is very little room for movement so that will wait for another project.