Fast AC train emergency rescheduling using an event driven approach

The paper reports the development and implementation of an algorithm for the online timetable checking and rescheduling of the 50 Hz single-phase overhead current collection catenary system currently in operation in Hong Kong. Running as an online consultant on a personal computer, this algorithm allows operating personnel to perform checking of a proposed timetable under various feeding conditions, to see whether runtime and traffic requirements can be met without causing any overloading. By using the event-driven approach, the computing time for checking each timetable is extremely fast. Owing to simplicity of this approach, various rescheduling schemes may be devised to suit different requirements of operational sophistication. This implies that many timetables may be examined, and users are able to find out effects of their own choice of rescheduling schemes in each case. The valid timetable or reschedule is then transferred to the full-scaled simulation package for further investigations. An accurate evaluation of train and system operating schedule involves the solution of many simultaneous differential equations. The paper shows how the overall computational efficiency may be improved by using the timetable checking/rescheduling scheme to filter the ‘bad’ data before being entered and verified in detailed simulations.