To the question of the stability of the metro in the brake mode

Abstract

According to the recommended ratio between the number of buses of different classes used in large cities, three-quarters of the bus fleet of a city with a population of more than 1 million inhabitants should be buses of large and especially large class. The greatest effect of using buses of large and especially large class is achieved in the BRT system.

The use of multi-link both freight and passenger trains should be confirmed not only by progressive transport legislation, but also by solving certain technical problems aimed at ensuring the high safety of trains and the entire traffic flow. At the same time, it is very important to ensure the stability of the vehicle in boundary modes so that it remains within the overall corridor.

Conducted studies to date have proved that the most dangerous in terms of ensuring the stability of the road train in emergency braking is the onboard non-uniformity of braking forces, and with increasing the initial speed of braking, non-uniformity of action of the brake mechanisms on wheels of the same axles of cars and road trains, significantly angular deviations.

It is shown that a generic parameter characterizing the stability of straight-line movement of a three-lane metro bus in braking mode should be taken to be the initial speed of movement at which the bus and trailer links do not extend beyond the width of the lane. According to this criterion, the initial braking speeds are obtained, which ensure the stability of the metrobus with both a guided and an unmanaged second trailer. These velocities were 12.5 and 16.5 m / s, respectively, when the coefficient of adhesion of the wheels to the support surface within j = 0.7 and the moment of non-uniformity of the braking forces on the axles of the trailers within 8000 Nm were respectively. This must be taken into account when determining the stability of the metrobus in braking mode.