Scientific paper ID 2152 : 2021/3

Automated trains determine their location onto the railway tracks by themselves and report it to the control center. The paper aims to provide an overview of modern types of on-board sensors that meet the challenge of the strong norms for precise positioning of metro trains. The report examines a typical set of specialized on-board equipment (radar, odometer (pulse generator) and balise antenna) and typical location onto the train. The emphasis is on the joint work of the sensors – the odometry, a vital part of the CBTC signaling systems. The train location onto the railway tracks, based on information provided by the radars and the odometers, is determined with a tolerance, the upper and lower limits of which may vary. A train passing over a balise and the corresponding ”reading” of its telegram increases the precision of the positioning of the train within the limits of some narrow tolerance. It is determined by the train balise antenna pattern and the location of the balise under it. The error of determining the train location can be with plus or minus. Given this, the signaling system assumes that the train occupies a section of the track ± the inaccuracy at the time of measurement, i.e. the train is artificially extended. When passing over a balise, the signalling system takes this fact into account and returns the actual length of the train. In conclusion, odometry is vital for both passengers’ safety and comfort.