Regional Transportation District light rail trains are back on track in downtown Denver’s business district loop after four months of construction and closures.

The D, H, and L light rail lines returned to normal service in both directions around the downtown business district loop. The loop closed on May 26, when RTD began reconstructing its outdated, 30-year-old track at five intersections.

Throughout the summer, the D and H lines detoured to Union Station, while the L line was suspended. All business district lines will return to their normal 15-minute increment services, while the H line will be 30-minute intervals, according to RTD spokesperson Pauline Haberman.

Since construction finished three weeks ahead of schedule, RTD ran light rail trains on the tracks to train new drivers and test the tracks.

“All the testing has gone according to plan, and everything is opening as promised,” Haberman said.

Summer-long construction resulted in downtown road closures and increased traffic surrounding five intersections:

• California and 17th streets
• Stout and 15th streets
• Stout and 17th streets
• California and 15th streets
• Broadway and Welton Street

RTD officials said it is doing a full-depth reconstruction of the Downtown Loop, which first began service in 1994, with a goal of improving safety and mobility, replacing aging infrastructure, and extending the life of the light rail network.

The initial phase focused on the five segments of “at-grade rail” and intersections in the downtown loop.

Haberman said RTD chose Sunday as the day to reopen because it’s one of three days during the year RTD changes its service times.

Changes include the H line extending its service frequency to 30 minutes. Another change is the W line will operate at a 15-minute frequency on weekdays from 6 a.m. to 6 p.m. along the full alignment.

A notable change is that RTD’s Free MallRide, along 17th and 15th streets, has been restored to five-minute frequency.