Some time ago I picked up a Williams 773 diecast Hudson. Didn’t pay a lot for I was mainly interested in its tender for another project. This version came with a prototypical cab number and a full scale, what some might call a 700T tender, instead of the smaller 2426 tender that the 773s came with.
This engine did suffer from jack rabbit starts that most Williams Post War reproductions seemed plagued with. It came with a 9:1 gearbox and despite cautions by master craftsman Harmonyards that a replacement motor would not solve this problem I decided to try a few that I had found along the way. That included a 24 volt motor and 2 12 volt motors spec’ed at 2000 rpm vs the typical 5000 RPM.
I used a ERR Cruise Commander set at one speed step and 100 speed steps to drive all the motors.
Here is what I started with.
This is the slowest the engine would run with any of the six that I tried though one smaller Buehler Motor rated at 2000 RPMs did turn slower it did not have enough torque to start a train.
I came to the conclusion like Pat did that no motor was going to solve this problem and the fix was going to be a new gearbox with a higher (numerically) gear ratio. I was able to find a NWSL idler gearbox on the Bay with a 23:1 gear ratio, closer to the 18-20:1 found in most MTH and Lionel scale steam engines.
I also settled on a Pittman 8700 series motor as it was small enough to fit in the boiler freeing up the cab after milling out some metal.
This is the final setup showing one speed step and flat out. I lose some top speed but it seems fast enough if not 100 mph.
This is the mod to the boiler.
And how the cab looks now.
Now back together awaiting detailing.