Name a popular MTA smartphone application.

MTA Subway Time is a widely recognized smartphone application that provides real-time arrival information for subway trains in New York City. This application was developed by the Metropolitan Transportation Authority (MTA) to enhance the commuting experience by allowing users to check the departure times of trains at specific stations. Users can easily access train schedules, alerts, and map services directly from their mobile devices, making it convenient for commuters to plan their travels more effectively.

The app's primary feature is its ability to deliver up-to-the-minute data on when trains are expected to arrive, which helps mitigate wait times and improves overall efficiency for riders on the subway system. This is particularly valuable given the complexities and sometimes unpredictable nature of urban transit systems.