REGISTER

Paul Szacsvay B.E. (Elec) M. Admin. MlRSE MIE(Aust)

Principal Signalling Engineer Rail Infrastructure Corporation of NSW

It took two decades from the introduction of LED (light-emitting diode) technology, for it to develop to the stage where it  first became viable for use in railway signals. In the five years since, manufacturers have made great strides in improving LED colours, light output and efficiency, and LEDs have become a serious competitor for conventional signalling light sources. There is now almost no limit to the signalling applications in which LEDs may be found.

As experience grew, the initially belief that LEDs offered an almost perfect signalling light source was tempered by
about the idiosyncrasies of the technology.

There is a proliferation of quality technical data available on the technology of LEDs and this paper does not go over that ground. Rather it describes the New South Wales experience with the introduction and proliferation of LED signals, the unexpected problems encounted, and the solution found. Despite the problems described, there is no thought of considering a return from LEDS to incadescent light in signals.

It concludes by proposing a basic specification for LED signal light sources, to achieve common standard for interfacing and monitoring LED signals.