1. Field of the Invention
The present invention relates to a train control system, and more specifically, relates to a train control system that can reliably secure a sufficient safety buffer and can enable safer travel control or safer brake control of a train.
2. Description of Related Art
Conventionally, as a train location detection system that detects a train location of a train travelling on a track, a tachometer-generator type train location detection system, in which a tachometer generator is connected to an axle of the train, and a travel distance from a predetermined reference location is calculated based on a pulse output signal generated according to rotational motion of the axle, and then a train location at that time is detected based on the calculated travel distance, is known.
Furthermore, conventionally, in a train control system using a so-called radio distance measurement system, a vehicle radio set is mounted on a train, and a wireless network is formed between the vehicle radio set and a plurality of wayside radio sets, which is spatially separated and disposed along a wayside of the track on which the train travels, and then, a wireless propagation delay (time) between an on-board antenna of the vehicle radio set and a wayside antenna of the wayside radio set is measured, to detect a train location, so that the train control is performed based on the detected train location.
Furthermore, as such a train control system, conventionally, for example, a technique including: a wireless train location detecting unit that detects a train location on a predetermined track based on a propagation time of a radio wave between a vehicle radio set mounted on a train travelling on the predetermined track and a ground radio set disposed at a predetermined location on the ground; a travel distance calculating unit that calculates a travel distance of the train on the predetermined track based on an output signal of a tachometer generator connected to an axle of the train; a temporary reference location setting unit that sets the detected train location detected by the wireless train location detecting unit as a predetermined temporary reference location; and a train location detection calculating unit that detects a train location on the predetermined track based on the temporary reference location set by the temporary reference location setting unit and based on the travel distance calculated by the travel distance calculating unit, has been disclosed (see, Japanese Laid-open Patent Application Publication No. 2007-331629,for example).
According to such a conventional technique, in calculating the travel distance of the train by the tachometer generator, the calculated travel distance may include an error due to slipping or sliding of wheels during the train travelling, and thus, with respect to the train location, safety buffers are set in front of and behind the train, to allow a margin of error of the detected train location, so that even if an error occurs between an actual train location and the calculated train location, the safety can be ensured.
However, since the safety buffer is set according to the detected location of the train and running speed of the train, the safety buffer is set to be short when the running speed of the train is low. Thus, depending on the error between the actual train location and the calculated train location, there might have been a problem in that it may be difficult to secure a sufficient safety buffer.