Six of the Regional Transportation District’s light rail lines were delayed for more than an hour Monday morning due to “mechanical issues,” RTD officials said. The initial mechanical issues, which caused trains to pull out of the station late and canceled multiple early-morning light rail trips, were most resolved around 7:30 a.m., according to RTD officials. Residual delays caused by the morning back-ups are possible on five of the affected lines and L Line remains out of service, RTD officials said. RTD officials said the “greater than 60-minute delay” affected: D Line, which runs from the 18th & California Station to the Littleton-Mineral Station and has reopened; E Line, which runs from Union Station to RidgeGate Parkway Station and has reopened; H Line, which runs from the 18th & California Station to the Florida Station and has reopened; L Line, which runs from the 30th & Downing Station to the Stout Station and remains closed; R Line, which runs from Lincoln Station to Peoria Station and has reopened; W Line, which runs from Union Station to the Jefferson County Government Center-Golden Station and has reopened. D Line, E Line, R Line and H Line all had morning light rail trips canceled and continue to experience up to 30-minute delays due to speed restrictions in track areas undergoing maintenance. The remaining light rail and commuter rail lines were not affected by the delay, including: A Line, which runs from Union Station to the Denver Airport Station; B Line, which runs from Union Station to Westminster Station; G Line, which runs from Union Station to Wheat Ridge Ward Station; N Line, which runs from Union Station to the Eastlake & 124th Station. Related Articles Transportation | U.S. 50 bridge over Blue Mesa Reservoir reopens after months-long closure, construction Transportation | U.S. 550 reopens between Ouray and Silverton after rockslide closes highway Transportation | Delta flight lands safely at DIA after midair “mechanical issue” damaged plane’s nose Transportation | More than 500 flights delayed and canceled at DIA as winter weather tapers off Transportation | Colorado road conditions: Denver area reopens, while plains highways remain closed No information about what mechanical issue caused the delay was available Monday morning. Tina Jaquez, a spokeswoman for RTD, said Monday morning’s priority was rolling out as many trains as possible for commuters before turning to investigate the cause. This is a developing story and will be updated.  Get more Colorado news by signing up for our daily Your Morning Dozen email newsletter.