Here are some images related to the Skookum page. This is a scrapbook of photos on various topics along with my reaction.
Powered Drive Line
This is a 3-1 kit bash by Bob Boudreau. It shows his approach to articulation of a 2-4-4-0 saddle tanker. Note that his front truck pivots under the boiler shell and is unattached to the rear truck unit. I love his detailing. Here is how he approached the rear truck unit that involved attaching the rear cylinder to the rear four set of derive wheels. This is an outside frame set but a similar concept could be used with the inside frame set.
This shows the front and rear drive components. Of course Bob’s model was static. He didn’t need to deal with powering the locomotive. The challenge in the Roundhouse kit is the motor normally mounts in the rear of the locomotive boiler. But power is delivered to the second driver pair in the front unit. That delivery is complicated by the fact the cylinder yoke for the second pair of cylinders is mounted in between.
One option is to install two small can motors (NWSL 1220S), each powering a driver block. Given I’m building a logging Mallet and using the boiler-tank-cab-bunker unit that came with the 3 in 1 kit, There may be sufficient room for two motors, even allowing the front driver block to pivot as the tanker shell extends almost to the front cylinders.
Another option would be to take the approach in this drawing from the NWSL web site. I have the middle unit on order as well as both motors commonly used with these locomotives. the angled approach may be able to go over the middle set of cylinders.
Once the middle set of parts (0.3 Mod idler gear) and I have both sizes of motors, I’ll take the approach that makes the most sense.