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НаименованиеA System for Brake Equipment Testing and Checkup

 

The control and the maintenance of the braking system of a train are surprisingly complex. The braking mechanism uses a pneumatic cylinder on each car. The cylinders are connected to a main air line that can be up to 2 km (1.26 mi.) long and connects to a pressure generator in the engine cab. Each car also has a local reserve tank for emergencies. The braking algorithm is a function of many factors from length and weight to temperature and track grade. In order to use these algorithms, it is critical that the braking systems on all the cars are within specifications.

Inspecting these systems is very time intensive. Failure to do this properly could lead to catastrophic failures. For example, if the brakes lock on a car in the middle of the train, the car and those behind it can discouple, or those behind it could derail. The decision was made to use computers not only to optimize trains braking but also to perform regular and automatic testing.

MOBILE LABORATORY

To do this we first converted a train car to a mobile laboratory, so that it could be added to any train. Our equipment communicates via UHF radio with data capture stations located in the locomotive, in a car in the middle of the train, and in the caboose. The data capture stations in turn communicate with telemetering stations located on each car. We not only log parameters from the cars, but we also take into account the total weight and lengths of the trains, the weather, track conditions and track grades. By having test runs of many sizes of trains in different geographies and different seasons, we were able to accumulate a large data base from which we derived the parameters to use in the control algorithms.

CORE SOFTWARE IN MODULAR HARDWARE

All telemetering stations have the same core of software and modular hardware. These are installed in metal boxes under each car. The telemetering stations use the multitasking real-time OS, RT Kernel and communicate using the AX.25.2 protocol. We operate at 1200 baud, because data rates are low and the lower baud rate gives us higher reliability. The systems are subjected to long term, severe vibration and outside temperatures as low as -50єC (inside box temperature) to more than 60єC. We found the Octagon MicroPC computers to be very reliable even under these extreme conditions.

The authors of this article represent the staff of the scientific production center, INFOTRANS, Samara, Russia.


A look inside the telemetering box
shows the compact system.

ВTelemetering station
before installation into
train car.

Telemetering station installed
under train car.

By Valery Zasov, Sergey Ivanov, Valery Kachur, Victor Pimanov

Valeriy Zasov,  Sergey Ivanov,  Basiliy Kachur,  Victor Pimanov