An audible train warning for track maintenance personnel

British Rail track maintenance staff currently use a portable warning device to provide audible warning of approaching trains. The audible signal comprises a train warning signal, which is continuous and the same signal broken into a series of discrete 'bleeps' to signify that it is safe to work. If the audible signal ceases entirely when bleeping then men could continue to work without protection. The study reported in this paper was in two parts. The first part, a laboratory study, compared response times to the sudden disappearance of the bleeping signal for four different lengths of interval between bleeps. The second part, a field study, sought to establish how operational conditions influenced response times for the interval with the shortest response time in the laboratory. The main recommendation from the study was that the interval should be shortened from the 7 s specified at the time the study was undertaken, to 2 s, in order to facilitate quicker responses to the absence of the bleeping signal.