Kato FEF-3 mechanism dimensions?

[thbguy]

Hello all,

I am slowly working my way back into the hobby and am intrigued about the possibilities that the Kato FEF-3 mechanism might have to offer (if it is the right size for my CN Northern aspirations). The prototype is too big to use, but N-scale Mfrs of steam usually either have to fudge the driver size, or driver wheelbase (or both) to get the right overall dimensions for the locomotive. This is because in N-scale, we have to accommodate wheel flange size.

For example, the BLI Pennsy M1a is just about perfect for CNR spoked driver Mountains and Northerns because the driver wheelbase looks to be just over 19' 6" (haven't unpacked/found my calipers yet, but it is pretty close), rather than the 18'10" on the prototype. Which suits me just fine, since almost all CNR 4-8-2 and 4-8-4 driver wheelbases are 19'6"!   

So, I am looking for someone to grab their calipers and measure the following on their Kato FEF-3:
(Actual mm/inches or N-scale)
           Driver size (without the flange)
           Axle to axle spacing for the driving wheels
           Axle to axle spacing for the lead truck

Really appreciate the help.
Michael Livingston

[robert3985]

Because of the brake and other details, it's not possible to get an ideal tangent measurement on the Kato FEF's drivers...at least with any of my calipers.  However, I took several measurements with the caliper jaws butting against the base of the flange on the first rear driver on the engineer side and got consistent +-.002" measurements that averaged .489"dia.

I eyeballed the center of the driver and lead truck axles and got .552" for the driver axle spacing and .490" for the lead truck axle spacing.

Cheerio!
Bob Gilmore

[thbguy]

Thanks Bob!

Ok, so that means that the dimensions for the Kato FEF-3 in N-scale are approximately
~     78" Driver size (without the flange)
~ 22' 0" Axle to axle spacing for the driving wheels
~   7' 4" Axle to axle spacing for the lead truck

Unfortunately, that doesn't give me the chassis I need to create a fleet of later CNR Northerns.
Maybe Broadway Limited will come out with a version of the Pennsy Mountain with boxpok drivers!

Thanks again for the help!
Michael Livingston

[craigolio1]

I don't model CN but I would build a mode of one of those streamlined beauties for sure!  Would look awesome next to my Royal Hudson. If you ever come up with a CAD design or a kitbash please post progress.

Craig