ABS failure diagnosis charts for a blocked CL

The Automatic Block Signal installations (ABS) is a system of powering and receiving circuits that ensure train traffic command, control, and signals between two consecutive train stations. The circuits are usually electronically or electrodynamically synchronized. Because the distance between two stations is at least 4 kilometers, any failure to these installations cause long traffic delays, especially since the maintenance staff must travel on foot to the site of the failure. To fix failures in the operation of BLA installations it is required that the maintenance staff is well acquainted with the system's wiring diagrams and their interrelations. The complexity of the wiring diagrams poses some problems in failure fixes. To ease the decision taking process in failure detection we present here diagnosis charts that lead to a quick and correct remedy decision. The diagnosis charts presented here are to be applied for cases when the current line (CL) is signaled as being occupied by rolling stock, but is in reality empty.