Across the United States, transit systems are confronting the same dilemma: how to modernize aging infrastructure while meeting the expectations of a data-driven era. Few places illustrate this challenge better than New York City, home to the country’s largest and most complex subway network. In recent years, a quiet revolution has begun within the city’s transit agencies, where data analysis, automation, and digital innovation are reshaping how safety and reliability are managed.
Working with the Metropolitan Transportation Authority (MTA), Shijie Liu has witnessed firsthand how data can transform infrastructure maintenance. Track geometry information—once collected manually and analyzed sporadically—is now captured continuously through advanced sensors and reviewed with predictive algorithms. These models help engineers detect subtle deviations long before they become structural risks. This shift from reactive to predictive maintenance has reduced service interruptions, improved worker safety, and saved millions in repair costs. For more than four million New Yorkers who rely on the subway every day, those improvements translate directly into safer and more dependable service.
Liu’s experiences outside the MTA further demonstrate how this data-driven mindset is spreading across the transit industry. On September 25, 2025, he participated in The Future of Public Transit forum at Cornell Tech, which brought together academics, public officials, and engineers to discuss the next decade of mobility. Two sessions stood out: “Rising to the Challenge: Climate Resilience in NYC Transit Infrastructure” and “Digital Innovation in Public Transit.” Both underscored that modernization is not merely about technology; it is about integrating environmental resilience and digital intelligence into long-term infrastructure strategy. Conversations with researchers from Cornell Tech and NYC Transit’s innovation office highlighted how data platforms can align with federal climate-adaptation goals while improving operational performance.
Earlier in the year, Liu attended the Smart City Expo USA at the Javits Center, held on April 2–3, 2025. There, policymakers and technology leaders from across the nation debated how digital tools could build more equitable, sustainable, and efficient cities. Discussions of open data frameworks and interoperable systems resonated strongly with Liu’s work at the MTA, where cross-agency data integration remains both a technical and cultural challenge. These national dialogues emphasized that public transportation modernization depends as much on collaboration and transparency as on engineering breakthroughs.
New York’s experience offers several lessons for the nation.
First, integration is essential. Data must flow seamlessly between departments—planning, operations, and maintenance—to allow informed, coordinated decision-making.
Second, predictive analytics should replace reactive management. Investing in early-warning systems for track wear, signal failures, and passenger flow prevents disruptions before they occur.
Third, open collaboration with universities and the private sector accelerates innovation. Partnerships like the MTA’s pilot projects with research institutions demonstrate how government agencies can adapt to technological change while maintaining public accountability.
Looking ahead, artificial intelligence and automation will define the next frontier of transit modernization. Machine-learning models can optimize train scheduling in real time, while automated inspection systems can identify defects invisible to the human eye. Digital-twin simulations of entire subway lines may soon allow engineers to test maintenance strategies virtually before implementation. Rather than replacing human expertise, Liu sees these technologies as enhancing it—allowing engineers and operators to focus on higher-value problem-solving and long-term system resilience.
To Liu, the modernization of America’s transit networks represents not just an engineering challenge but a national imperative. Efficient, safe, and sustainable transportation systems are central to economic growth, climate resilience, and quality of life. New York City’s progress shows that when public agencies embrace data as infrastructure, they unlock innovation that benefits not only a single city but the entire country. From predictive maintenance to climate resilience, the lessons learned here can guide a new generation of engineers and policymakers in building a smarter, more connected America.
