A portable, single-fixation, magnetic derailment mitigation device may be fixed on a rail track for measuring the deflection of the rail track. The magnetically fixing device is used for measuring vertical track deflection (sleeper voids), horizontal track deflection, ambient and rail temperature, rail angle, vibration, displacement, and location. The derailment mitigation device sends digital notifications and/or alarms during the live train and/or freight operations to help prevent derailments, rail buckles, breaks, and pull apart. The measured data and/or all events obtained from the derailment mitigation device is stored in the data storage such as cloud storage and viewed from any smart devices.