Methods, devices, and systems for automatically detecting, tracking, and validating transit journeys are provided. A transit data processing engine receives sensory data gathered by a plurality of sensors of a mobile device registered for automatic tracking of transit journeys and detects, based on transit data of one or more transit agencies and a first set of the sensory data, a potential transit event with the one or more transit agencies. Based on the transit data and a second set of the sensory data, received subsequently to the first set of the sensory data, the processing engine determines then whether the potential transit event defines a transit journey having a starting point with the one or more transit agencies. If the potential transit event defines the transit journey, the transit data processing engine continues to analyse the sensory data being received to detect an ending point of the transit journey.