Special edition paper

The axle box temperature heating detection system was developed for early detection of abnormal heating of components of axle bearings—important running devices for railway rolling stock— so that critical accidents could be prevented.1) 2) 3) The developed system is now being deployed for major lines in the greater Tokyo area. Early detection of abnormality of bearings is needed in regions with heavy snowfall too, so we examined functions for cold and snow resistance to apply the system for the greater Tokyo area to cold regions. We installed a prototype system that reflected the examination results at Ugo-Ushijima Station on the Uetsu Line (in Akita City) in the period from December 2010 to September 2011. Using that, we investigated the effects low temperature, snow cover, and snowfall have on performance. Development for System for Cold Regions2 The developed system measures temperature of components of an axle box that holds bearings. Specifically, it is a system using contactless infrared temperature sensors (infrared radiation thermometers) installed facing axle boxes of running train cars as shown in Fig. 1. The system measures surface temperature of axle boxes obliquely from below, and it gives an alert if it detects that a designated temperature is exceeded. Wheel detectors that are installed on the rail determine the position of each axle box. By using three wheel detectors on each side, velocity of passing trains is calculated to identify the position of the axles. The system has a built-in heater to keep ambient temperature at 5 ºC or higher for stable operation of temperature sensors. As the sensors are an infrared type, there should be no obstacles between the system and the axle box to be measured. Furthermore, to apply the current system to cold regions, cold and snow resistance has to be enhanced. Taking into account those conditions and installation to lines along the coast of the Japan Sea (Uetsu Line and Ou Line), we set the following specification values for cold regions based on weather data in the previous five years at Niitsu, Akita, Odate and Hirosaki