Movement of a railway car rolling down a classification hump with a tailwind

Abstract

The purpose of this paper is to calculate kinematic parameters of a railway car moving with a tailwind for designing a classification hump. The calculation of kinematic parameters is based on the d'Alembert principle, and the physical speed and distance formula for uniformly accelerated or uniformly decelerated motions of a body. By determining a difference between two components - gravitational force of a car and the resistance force of all kinds (frictional resistance, air and wind resistance, resistance from switches and curves, snow and frost resistance), which take place at different sections of a hump profile, the authors calculated the car acceleration at various types of car resistance, as well as time and speed of its movement. Acceleration, time and speed were plotted as a function of the length of a hump profile section. The research results suggest that permissible impact velocities of cars can be achieved by changing profiles of projected hump sections or by using additional hump retarders.

About designing the height of the first profile of the marshalling hump

“…In the last formula n and ∑α ac find from the plan of a neck of marshalling tracks (see p. 141 in [13]). Analysis of the formula (17) shows that it is empirical, has no theoretical basis, and, at the same time, it is determined h ac1 depending on the average speed of the car on the route (section) rolling, i.е. h ac1 =f(n, ∑α ac , [v m ]).…”

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“…Согласно формуле (4) в [21], полученное на основе теоремы о движении центра масс системы материальных точек, приводим математическое описание движения вагона в зоне затормаживания на участках тормозных позиции (ТП) сортировочной горки в виде (см. формулу (12) в [19]…”

“…Заметим, что последние выражения аналогичны с формулой (18) в [19] для определения скорости движения тела по неидеальной (с трением) наклонной плоскости, полученные согласно принципу Даламбера.…”