Where Is My Train: How this app track Train without internet in india ? | System design, Engineering and Programming

Hi guys My name is Akash Vishwakarma. Where Is My Train is a landmark Indian app that solved railway tracking by engineering for poor connectivity. Built by Sigmoid Labs and later acquired by Google, it uses cell-tower signals, cached schedules, and crowdsourced data to estimate train positions offline. Its success lies in constraint-driven design, edge intelligence, and pragmatic system architecture rather than flashy tech.