Arc bridge and slope for OS-Railway

thingiverse

This page features a bridge and slope, both of which are massive! The arc bridge has an impressive span of 80cm. It's built on 4pcs of 200mm standard track, available on the general track page: http://www.thingiverse.com/thing:2146361. Important note: Use 100% infill to ensure structural integrity. The arc pieces are already hollowed out, so reducing infill will likely cause problems. This print is a bit experimental, requiring sanding and tinkering to get it working smoothly. The prototype version differs from the STL's due to some issues I tried to fix. On the prototype, I tested 1mm thick walls on some parts, but they cracked easily when assembling the arc. In contrast, pieces with 2mm walls held together perfectly, so I've updated the design to use 2mm wall thickness throughout. The arc members have fastening holes for track supports and joiner pieces. Two joiners are used between the arcs, as seen in the pictures, but four are included in the ready build plates. You can print more if needed, but they're not essential for structural integrity. If you want to use additional supports from the arc down to the track, create new ones with adapted lengths. I've included two lengths that worked well in this build, matching the track joints where support is most needed. Things to know about the slope: The slope parts are designed to be glued together (you can also screw the track holder joint and holder plate). Position isn't critical, so no guiding parts were added to the structure. I prioritized minimizing print time. The pillars are already hollowed out, so don't reduce infill – use 100%! Print Settings: Printer: Prusa i3 mk2 Rafts: No Supports: Yes Resolution: 0.25mm Infill: 100% Notes: Buildplate 2 and 3 of the bridge will need support for the slide-in-ends. (Support from build plate) All parts are designed to be printed with 100% infill, which is crucial due to material properties. Thin walls with an infill-mesh can be stiff but brittle, while a completely hollow part with thicker solid walls is much tougher and more flexible. In this application, the latter properties are essential for strength. For example, track joiners printed with less than 100% infill will easily break when disassembling the track layout, whereas those printed 100% solid can withstand twisting and bending. Post-Printing: If you experience trouble assembling the track, check if there are any edges sticking out. This is common when the first layer gets squeezed, causing tiny edges where that layer is wider. Sanding paper or a file will fix this issue. I designed this bridge using Fusion 360.