Trinity Railway Express

The Trinity Railway Express (TRE; reporting mark TRWX) is a commuter rail service in the Dallas–Fort Worth metroplex, Texas, United States. It was established by an interlocal agreement between Dallas Area Rapid Transit (DART) and Trinity Metro. Each transit authority owns a 50% stake in the joint rail project and contractor Herzog Transit Services operates the line. The TRE began operating in December 1996. In 2025, the system had a ridership of 1,337,600, or about 6,700 per weekday as of the second quarter of 2026, making it the seventeenth most-ridden commuter rail system in the United States. Before 2006, the TRE was typically shown as a green line on DART maps and therefore was sometimes referred to as the "Green Line," but this was not an official designation. In 2006, DART chose green as the color for its new light rail route, the Green Line. Since 2006, the TRE has been shown as a dark blue line on DART maps.