I’ve had a few two-axle freight cars from LGB over the years, both from their Toytrain range as well as their regular range, with different wheel bases. All of them had one thing in common: the trucks (or bogies, for the UK visitors) did not realign properly to the center when leaving curves. Even worse, if the trucks happened to be properly centered on a straight section of track, and the train entered a tighter curve (the dreadful R1s…), they would not even align to the inside of the curve, yet still point straight. With metal wheels equipped on all rolling stock, this ended up in squeaky drama. Sometimes this would even lead to derailment on switches, although I admit this could be due to my bad track work at the time ;-).
I am aware that squeaky noises are actually kind of prototypical, but if I want realistic sounds, I’ll add a sound decoder of some sorts so I can decide for myself to turn off the noise whenever I want :-).
A few years later now, I only have a set of somewhat-prototypical HSB freight cars left (LGB #40030), which suffered the same fate. So I went ahead to design something with three objectives in mind: centering the trucks automatically to avoid any misalignment, yet allowing some flexibility to still navigate around tight curves if needed. Finally, the end product should be a universal design that could be applied to any (modern) two-axle car from LGB with a single screw.
I ended up designing a centering spring that could be 3D printed. I have a FFF 3D printer at home (I started with a Velleman Vertex K8400, now I have a Prusa i3 MK3S+), but at these small sizes and the requirement for the component to be durable and flexible, I printed via Shapeways. To make it cost efficient, I printed 48 at the same time, so I have some stock…
Installation is easy: place the centering spring, and lock it in place with a common size screw.
Here the truck is centered, the flexible ‘arms’ push towards the bracing on the frame.
… and the ‘arms’ are flexible enough to still allow movements of the trucks to negotiate tighter curves.
In combination with S-KuPLiX couplers (which I prefer anyway, compared to the hideous hook-and-loop couplers that come by default from many G scale manufacturers), this has worked very well in both push and pull operation.
So for these centering springs, I see two use cases:
– For people who run on large radii, who don’t need the swiveling functionality at all, and thus just need to keep their trucks centered, yet still having flexibility if their rolling stock would ever run on a smaller radii layout.
– For people who run on smaller radii, who ideally have narrow(er) couplers installed to have proper alignment of trucks in curves or on straights.