The title pretty well describes the following except to note that you are not confined to just HOn3. This conversion can be used for any gauge between HOn3 (10.5 mm) and standard gauge HO. The gear box and the tabs that hold its cover on are probably too wide to do HOn30 (9mm or HOe gauge).
Another thing this illustrates is that getting into narrowgauge doesn’t have to be expensive. This conversion can be accomplished for a little over $100 and yields a smooth running Kato-powered loco that can pull the wallpaper off the wall. While it won’t scratch the steam itch, it is equipped with a steam generator to enable it to pull passenger trains.
First a side by side comparison between one of my NW2M locos and a yet-to-be-modified standard gauge Kato NW2.
Notable is the loss of the tapered hood section, replaced by a full width hood all the way to the cab. This provides space to model the steam generator and dynamic brakes (conceptually) while providing extra space to locate the decoder (physically) without the need to hack at the chassis weight.
Getting the shell off the chassis is a bit tricky. Here is a link to Kato’s instructions:
The small retaining nubs cast into the chassis halves should be filed down to make things much easier the next time.
This pic illustrates what you’ll find once the halves of the chassis are split apart. It’s a lot like many N scale locos with each half of the chassis isolated from each other by some plastic bushings.
With a tested, running narrowgauge chassis you’re ready to make it look good. If you are a modeler of one of the road names that Kato decorated this model from, you may even have little need for painting, but YMMV. Since I’m doing a version of the Rio Grande, I’ve been able to obtain complete shells with the details, etc and needed to do little painting. You’ll need a complete shell plus enough of another one to cut the center section out to extend the straight hood all the way to the cab.
Here’s a shell with another sliced up in front of it, with one of my earlier NW2M (as I call these) locos in the background. I’ve started the first cut on what will be the main shell once it’s modded.
Here the first cut is finished.
In this pic, the donor shell (with a white Southern stripe at its bottom) has been cut to just the length needed to fill in and keep the cab flush with the back of the main chassis. The cab still needs to be chopped in this pic.
This pic illustrates how far to cut the cab down. I should’ve used the Rio Grande one instead and I could’ve saved a bunch of conspicuity stripes, but this one will be a little different.
This is the modded shell awaiting paint and final application of details.
I managed to salvge the light packages and reconnect front and rear easily with just the wirer supplied with the decoder. Got a few more pics to take to show how the cab, plows, and couplers attach.
Nice work, Mike. I do have a question…is it possible to press the axle shaft in the wheel? This way the shaft could stay the same length and might fit the pick up strip better.
It might be. You’d still need to trim the projections that hold the shaft that are cast as part of the gear. I didn’t evaluate closely, but with standard gauge the inner ends of the half axles are probably pretty lose to touching. I’ve never worried too much about being precise when I shorten the gear projections to accomodate HOn3, although doing so could be helpful with retaining minimum gauge.
This mechanism would work quite well with Sn3. The cab might need to be reworked for S scale. For instance, you probably don’t want to cut it shorter like I do for HOn3.
First, the cab retainers. Looks spooky, but I used 1/4"square plastic to the cab that fit into “battery box” enclosures I added next to the cab on the walkways.
Kato makes the walkways as a separate part. I glue the modded hood assemebly to this piece. You also will need to open up the included walkway where it narrows where the hood previously narrowed. Slice it open enough to better fit the widened hood there.
With the retaining dimples filed down, you need another way of retaining the shell. I added snowplows at each end. The couplers connect via a snap in retainer that was with the loco. I added a thick piece of plastic that snaps into the bottom part that the Kadee 714s I used have a suitable mount for their screw to be retained. With the chassis in place inside the shell, the coupler/rertainer assemblies snap in and protrude past the snowplows to keep things from falling apart when it’s picked up.
I used Details West PL-207 snowplows. The footboards are cut-off and the plow is applied in position so that it clears the track, but is low enough to allow the coupler to protrude at the right height. You’ll need to take a file to the center top of the plow to open up a slot for the coupler to set right.
The “dynamic brake” detail is a Details West WH-163, which is actually a EMD F unit winterization hatch. This is supplemented by vent screens on each side, which are FS-1303 Cannon and Company Inertial Filter Screens. A small bit of tubing and a steam generator vent faked up with a spare kit part complete this work on the widened part of the shell.
Awesome, Mike. The cab retainer idea is for sure something I’m going to use. I like the way that you take other parts, such as the winterization hatch, and use it for a completely different purpose. This build is very creative and you have done an excellent job!
