Recent Measuring of the Resistance to Forward Motion of Rolling Stock.

When carrying out research on the operation of trains at high speeds, the French National Railways succeeded in devising a more general method which gives reasonably accurate results when measuring the mechanical and aerodynamic forces affecting resistance to forward motion. The authors explain the principles of the testing methods employed, the results obtained with various conventional types of rolling stock before arriving at a formula valid for hauled or mechanically propelled trainsets. This formula, which assumes that the wind force is zero, takes account of the vehicles' main geometrical dimensions.