This document provides an overview of commuter rail systems in the United States. It discusses that commuter rail connects downtown city centers to surrounding suburbs, with 28 existing systems and over 6,600 commuter rail vehicles. The history section outlines that commuter rail originated from British technology imported in the 1830s and were originally privately owned before becoming public authorities by the 1970s. Major commuter rail systems are then described, including ridership and expenditure statistics for systems like MTA Long Island Railroad and Metro-North Railroad. New projects under development like MiTrain and TEX Rail in Michigan and Texas are also mentioned. Issues faced by commuter rail are outlined as well, such as safety concerns over accidents and delays from weather conditions.