Channel utilization by remote locomotive control systems using digital transmission

The railroad industry is successfully operating, co-channel, several radio controlled remote locomotive systems (slave locomotives) and cab signalling systems within radio range of each other through the use of high security digital transmission. The railroad radio service now has two pair of 450 MHz frequencies assigned nationwide for these systems. This paper will describe the extent these systems are presently being used and the methods employed to avoid intersystem interference while permitting sufficient air time to provide "real time" control and signalling to locomotives.