Measuring the settlement of exist railway’s subgrade is a difficult thing and the known detecting methods have several shortcomings

such as long test time

slow detection speed

displaying data indirectly observable and so on.A new method which can measure the settlement of exist railway’s subgrade automatically and real-timely is advanced

and structure of monitoring system is also introduced.The system adopted MSP430 microprocessor to control measuring device to monitor settlement automatically

and GPRS communication modules is used to transmit data to monitor center.Finally

the measurement data is displayed dynamically on the Internet

and the system will alarm automatically if something dangerous happens.The system can realize the automatic and real-time

high precise measurement of roadbed settlement.Moreover

the system is easy to use

and the cost for developing and operating is quite low.The testing system is applied on an existent railway in a city.