The rolling stock kits I have built are mostly wood with metal castings, metal straps, or metal rods for the detail parts such as brake rigging, grabirons, etc. Some, such as their tank car, kit #248, included a piece of PCV pipe for the tank with a cardboard wrapper.
Note that most of their kits do not include the trucks. The trucks they sell are metal. One additional thing I always do is drill out the journals and insert ball bearing races that I order from Great Big Trains (http://www.gbtrain.com) or purchase from an Ace Hardware store in Tucson, Arizona. I put these races in all of my rolling stock, whether scratch built or store bought, and they double the length of trains I can run.
Have fun with your trains
Even worse, the Dunkirk uses brass rod drive shafts from the gearbox to the trucks, and 90-degree twisted O-rings between the drive shafts and truck axles. It makes a horrible, high pitched whining sound but barely moves, and the O-rings break or burn from the friction within days, depending on how much you run it.
I just gave up after the first week and put it onto a shelf as a display curiosity.
If you're referring to Northeast Narrow Gauge in Wiscasset, Maine, I have built several of their 1:20.3 kits and have been very pleased with them.
The only one I didn't like is the 13 Ton Class B Dunkirk. The kit itself is not bad, but the drive system is horrible. I have shied away from any more of their locomotive kits in the belief that they may all use the same system as the Dunkirk.
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