Possibility of sensor network applying for railway signal system

Sensor technologies have significant roles for train operations, many sensors have been developed and installed. At present, performances of these sensors are high enough to ensure safety operations of trains, but not enough to maintain the stable work of signal devices. Therefore, advanced sensor system is expected. For example, a wireless communication system is desired because it has small influence to present systems. Sensor network is one promising solution. Its function of multi-hop transmitting easily realizes wireless networks. Implanting several sensor devices in a railroad crosstie and setting the crossties under rails, the sensor network automatically forms a communication path along the rail, where the resolution of sensing is around a meter and the path is flexible to reform. In addition, the MEMS technology will have large contribution to realize small but high performance sensor devices with low cost. By using such intelligent sensor devices, sensor network will realize the next generation of railroad control system.