In its continuous eandeavour to enhance safety in Railway operations, the Indian Railways is now adopting first ever unique modern technology for maintenance of its passenger coaches, wagons and locomotives. The new maintenance technique which uses acoustic method of diagnostics is known as Acoustic Bearing Detectors (ABD) and Wheel Impact Load Detectors (WILD).    When used in combination together they are known as Online Monitoring of Rolling Stock (OMRS) systems. This technique involves placing arrays of microphones and sensors that record the audible noise and forces generated by the running coaches, wagons and locomotives.    Conventional method to maintain passenger coaches, wagons and locomotives is to physically examine when these are in stationary condition at the maintenance depots.    Under the new technique, the faults in the Rolling stock can be detected while on run which is a big advantage as it will make maintenance faster reducing turn around time for Rolling stocks thereby ensuring availability of high number of wagons/coaches etc. for operation.    The OMRS equipment is so sensitive and accurate that it is often able to indicate the specific sub-component that is not behaving the way it should and therefore causing abnormal noise. Moreover, this can be monitored remotely using mobile communication facilities.    In the conventional method, it is nearly impossible to detect this problem unless major assemblies are completely dismantled and checked in the maintenance depot.