This paper substantiates the worth use of System-1 Evo, which was recently installed during shutdown 2021 at IFFCO Kalol plant. The process air compressor train consists of steam turbine driving LP & HP compressors through flexible coupling. HP compressor is driven by speed increase gear box. Complete compressor train is monitored by a Bently Nevada 3500 rack and system-1 Evo diagnostic software. Each bearing has 2 orthogonally oriented radial probes. This air compressor unit (101-J) had developed problem of very high vibrations, during plant startup of 2021 and plant could not be started due to it. System-1 Evo diagnostic software identified the cause of high vibration. Necessary corrective actions were taken accordingly and process air compressor unit and plant started smoothly.