HO Walschaerts Valve Gear Design

I need a fully parametric Walschaerts valve-gear model created in Fusion 360 for an HO-scale steam locomotive, and I need it right away. Every rod, link, pin, and eccentric must be present, dimensionally correct for HO, and constrained so I can animate the motion and make small adjustments without rebuilding the file.

Because the locomotive will eventually be both 3-D printed in brass and CNC-milled, clearances, tolerances, and realistic joint thicknesses are critical. I will supply the wheelbase, axle centres, and cylinder throw as soon as we start; you will translate those numbers into the classic Walschaerts geometry while keeping the parts printable/machinable at 1:87.

Deliverables
• Native Fusion 360 file with fully named components, joints, and parameters
• Step file for cross-platform use
• An exploded PDF drawing or 2-D export that labels every part for machining or printing
• Short screen-capture showing the assembled gear cycling through its motion without interference

Acceptance criteria: the assembly must run a full revolution freely in Fusion 360’s animation workspace, all joints must resolve, and overall dimensions must match the supplied HO frame sheet within ±0.05 mm.

If you have recent experience modelling miniature mechanisms in Fusion 360 and can start immediately, let’s get this moving today.