Our fast society cureates the desire for increasing train speeds to compete other transport modes. This paper discusses the influence of increasing maximum speed on the alignment, turnouts and capital costs. The unpleasant influence of centrifugal force which is developed when trains are passing on curved tracks made it necessary to take care of its alignment. The maximum speed should be defined as a function of cant, non-compensated centrifugal acceleration, and curve radius. For aerodynamic considerations, track centre spacing must be increased to avoid extra pressure on train sides. Turnouts must be studied in form of tangent switch rails, transition curve, small angle of crossings and movable frogs. Advantages and disadvantages of braking types must be discussed. Shoe, disc and rheostatic brakes are to be considered, and sipping problems caused by poor adhesion between wheels are rails have also to be discussed. The automatic train control system, laying and maintenance tolerances, and economic aspects are among the main points to be studied.
New graphical and analytical relations to evaluate the effect of increasing speed on cant, curve radius and on the non-compensated centrifugal acceleration are shown.
Hopefully these relations can help the designer either in choosing the alignment parameters or to improve the alignment for increasing speed on curved tracks. Finally, important formulae, tables and set of recommendation are presented.