In train traffic, traffic security installations failure recovery is time consuming, causing time delays the the railroad traffic. Automatic Block Signal Installations (ABS) are on type of installations that ensure railroad traffic security. To decrease the failure diagnosis and remedy times for ABS Installations in cases where the installations do not regularly invert, we defined a set of diagnosis charts. Based on these charts we devised a diagnosis software tool, called INVBla, which can be used by the technical maintenance staff on both mobile devices (tablet, smart phone) and PCs. The use of the INVBla diagnosis tool is a fast and secure tool that assists the maintenance staff in determining the failures in ABS regular inversion, triggered by dispatch commands, for a unified ABS installation depending on an Electrodynamic Centralized Traffic Control Station of type 4 (CED-CR4).