There is now a discussion on Burnsland about the pilot truck, with rare pictures of the truck detached from the engine.
Some observations I took from the thread:
- Disney used almost no bolted connections on the frame itself! Everything appears to be (heavily) welded. In one way it makes some sense given the scale of the truck, but I wonder how easy it is to perform maintenance. For example, if one of the braces crack?
- The transverse bar has a different profile–more trapezoidal than rectangular. That’s easy to fix, but it also appears to be “doubled”–having an inside and outside pair.
- I can finally see the center swing casting–but unfortunately the photos aren’t clear enough to show how it’s assembled. However, I think I have enough to make a good guess.
- I will revise the equalizer bars to be thinner.
- A good point was brought up that I give a bit of thought to previously. In actual pictures of the engine you will see the bottom of the leaf spring, and in the side profile of the truck I made, you do not. I believe this is attributed to the actual weight of the engine flattening the spring. The spring I model is a static solid body, so it cannot compress.
I’ve never drafted suspension system before and I’ll have to think about which state to show: compressed or uncompressed. The purpose of the drawing should govern first, but there’s a question of faithfulness representation of the engine “as seen” by the user.