From the above expression, it is found that the adhesion, that is, brake force is determined by the adhesion coefficientμ. The adhesion coefficient depends on the type of car, which tends to lower as speed increases.
The adhesion coefficient of a diesel rail car is shown by the following expression.
μ = 0.285 (1 + 0.114V) / (1 + 0.15V)
V: Velocity
(c) Deceleration of New Sprinter
From the above expression, a very high deceleration is obtained through calculation. However, it is not practical because there are many unstable factors including weather and rail surface state. In the case of a recent diesel rail car, the emergency deceleration is set to 4.7 km/h/s for the 283- series diesel rail car of JR Hokkaido.
According to the above actual data, it is estimated that the maximum speed of the New Sprinter can be improved up to 150 km/h by setting the emergency deceleration to 4.2 km/h/s.
(d) Adoption of glide readhesion system
To securely perform braking, it is effective to provide a glide readhesion system for immediately readhering a wheel even if the wheel glides due to rain or the like for each shaft.
5) Body tilting system
Because the forced body tilting system detects a curve by a gyro installed on the head car, it is difficult to tilt the head car and to control against sharply curved line
