I like narrowgauge diesels. There are a few prototypes, mostly outside the US, and there are some locos where narrowgauge can be spec-ed on what is usually a standard gauge chassis. Then there are ones that are pure fantasy, but I like to keep things believeable.
Here’s a pic of my first conversion. It’s Australian in origin, with a Powerline shell on a K&M Engineers HOn3 chassis. I added steam generator details and repainted it. It’s a strong puller, but the C-C trucks don’t like curves too much.
Here’s an Athearn conversion of a SW chassis that resembles a Whitcomb diesel. I bought it from jeepcaptain, who sells all sorts of NG diesel conversions on the popular auction site.
Then there are my GE 70-tonners, based on the Hauff brothers article in RMC.
My latest conversions are of Kato NW2s to what I call a NW2M. It’s based on an article by Raymond Hoppes in the August 2010 RMC, where he converted a NW2M to a replica of the Army 4700N experimental narrowgauge diesel. My mod adds a steam generator and dynamic brakes to the basic underpinnings provided by Hoppes.
It’s not that I don’t like steam. I’ve got a number of Blackstone locos, as well as several pieces of brass that I’m beginning to convert to DCC/sound. These conversions represent an economical way to add reliable motive power to my HOn3 system.