Sensitivity Analysis and Two-Stage Conceptual Design of an Electromechanical Rack-and-Pinion Carbody Tilting Mechanism for Passenger Railway Vehicles: A Preliminary Computational Assessment

This preliminary computational assessment examines an electromechanical carbody tilting concept (Kazakhstan Patent No. 37405): the carbody rotates on bogie-mounted rollers about a roll centre above its centre of gravity, driven by a servo pinion and an arc-shaped rack. A quasi-static model links seven design variables and ten vehicle, track and gear-load parameters, from 1520 mm rules, published data or assumptions, to the model speed limit, gauge clearance, actuator demand and ISO 6336 safety factors. Morris and Sobol' analyses, a two-stage design (NSGA-II layout, reliability-constrained gear sizing), Monte Carlo, drive-failure, wheel-unloading and rack-fastening estimates and a finite element cross-check were performed. In a first-order gauge check, a full-width coach can tilt at most 2.95°. A candidate layout with a 3.00 m carbody and a 2.8 m rack radius reaches a model-limited 130 km/h (conventional 101 km/h), or 116 km/h with a 100 mm lateral gauge allowance. Its conditional gear failure probabilities stay below 1% under the assumed uniform distributions but not under assumed correlations, wider load-factor ranges or model-error factors. After a drive failure the undamped carbody exceeds the gauge; an end stop, damper and brake are required. All speeds are model-limited, not operational limits, and require experimental validation.