Most articulated models are not the best pulling locomotives as they don’t have very good weight distribution. Most of the weight is usually centered over the front driver set so the rear drivers don’t add a lot of pulling power. The Akane models are no different in this regard as the original boiler weight is roughly centered over the front driver set.
The rear drivers are weighted through a very lightly spring loaded stud that just transfers enough weight to hold the drivers down on the track. The spring is so weak that it doesn’t add any effective pulling power. Here are a couple pictures showing the spring loaded foot for the rear drivers:
To improve the weight distribution on the rear drivers I made a few changes to rear of the locomotive. Since the Akane frame is a U channel it provides a convenient location to add additional weight. While the space isn’t too big it does allow for a weight of a couple of ounces. Here’s a picture of the weight that I added in the frame:
Since there’s only the one spring stud applying weight from the boiler there’s a limit as to how much weight can be applied. The rear portion of the locomotive must also still be able to articulate when the locomotive rounds curves. As a compromise I made a weight of a few ounces that I mounted in the boiler directly above the location of the spring stud. Here’s a picture of the boiler showing the original weight and the newly added weight over the spring stud.
To maintain the correct the balance across the locomotive I replaced the spring on the stud with a heaver spring recycled from a ball point pen. To adjust the spring correctly I placed the new weight on top of the stud and cut the length of the spring so that the stud was at the correct height when loaded with the additional weight. To help offset additional wear on the top of the stud I made a small wear cap out of Acetal plastic. Acetal is a self lubricating material that should slide better than the brass on brass of the original design. If the Acetal should wear out over time a new cap can be made. Here’s a close up picture of the wear cap:
Here are a couple of pictures showing the spring foot all put together with the new spring in place:
Page 5 - Last updated April 25, 2004