Performance Constraints Imposed by Increased Train Length and Their Countermeasures

In Alcatel's development of operational performance measurements for the Hong Kong West Rail project, which implements a SELTRAC automatic train control system, it was natural to anticipate some general increase in non-interference headway with the employment of long high-speed trains. Two general changes in our model of train operation were needed to support the headway requirement: incorporation of center of mass in safety distance calculations and the elimination of a reduced braking rate for non-scheduled stops. This paper will present further details of the problems encountered and the strategies developed to reconcile them. In particular, it will present the benefits of considering the train as a distributed mass about its center of mass. It will show that the center of mass can then be used to define the starting and stopping points for braking calculations within an energy conservation model. In addition, it will present the benefits and risks of increasing brake rate for non-scheduled stops.