It is generally recognized by FRA, AREMA, Amtrak, OSHA, and many other applicable authorities that the maximum acceptable rate of radial acceleration for passengers comfort is 0.1g, where ‘g’ is 9.81 m/s/s [1]. Jerk is limited to 0.03g/s [1]. Roll is limited to 1 deg/sec. In this paper all values computed with the aforesaid standard values are referred to as the maximum desirable values as these may be exceeded if needed. Currently there is no procedure in the literature to compute the maximum desirable values. From these comfort criteria the formulae for superelevation run off, rate of change of curvature, radius, and spiral angle etc. are derived. Applications of these formulae and further potential applications thereof are presented. This study is intended for conventional non-tilting train. The equilibrium (Eq), actual (Ea), and unbalance superelevation (Eu) run-off are calculated to be 45 mm/sec, 26 mm/sec and 19 mm/sec respectively. From the run-off rates, the maximum desirable actual and unbalance superlevation comes out to be 87 mm and 63 mm respectively. The desirable ratio between unbalance and actual super-elevation comes to be 0.72. This helps in proportioning equilibrium superelevation to ensure comfort. Equations of spiral length are derived by proportioning 3.33 sec’s ride with the maximum desirable values of superelevation and these equations are found to be exactly the same as those derived another way in the paper no. JRC 2010-36050.

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