What audible warning is required on an item of motive power?

There is a RISSB standard for audible warning devices on rollingstock, members should undertake a risk assessment process noting the location and operational environment in which the audible device is to be used in conjunction with making reference to the RISSB standard. As an example, there is a significant difference to the audible warning device required on mainline high speed rail operations to that of a low speed open access metropolitan rail operation (tram).