Nearly twenty years have passed since the introduction, on low traffic density lines in particular, of the electronic block system. Installations have aged, and this obsolescence has made some equipment difficult to maintain in service. Therefore, a new train control system aided by radio bases, capable of radio communications between a vehicle and ground equipment within a limited area around stations was developed, which while offering the same functionalities, was also a feasible replacement of the electronic block system (Fig 1).
A special feature of the present system utilizes existing installations such as track circuits, therefore it can be mainstreamed without large scale upgrading of facilities. Radio communications are achieved with 2.4GHz, which does not require any special licence and is accessible using generic radio technology. Furthermore a method was proposed to meet the need for correlating the on board device ID with the train number, overcoming limitations on the use of the onboard device, eliminating the requirement for a driver to set a departing route , and preventing early departures. The cost to introduce the developed system’s route control and blocking functions was estimated to be approximately 85% that of a semi-automatic block system including an automatic route control function. In addition, the on board device was connected to the ATP with continuous speed checking, therefore, the positioning of wayside radio equipment provides the means to achieve functions such as protective speed profile erasure. By virtue of these functions, it is possible to stop the train before a level crossing, even if the crossing alarm is not activated, which is hoped will contribute to raising safety around such locations (Fig 2). Line tests were performed to check the feasibility of the various functions.