A Metro Red Line train derailed in Silver Spring on Tuesday, after the operator ran a red light signal, the agency responsible for safety oversight of Metrorail said. No one was injured in the mishap in which two cars left the tracks.

Red Line service was suspended while investigators combed through the scene, next to the station platform, where the 7000-series rail cars sat askew and off the tracks.

“The preliminary suggestion is that they passed a red signal,” said Max Smith, spokesman for the Washington Metrorail Safety Commission. “We need to investigate why did that occur? What communications and issues happened? What happened with the switch? All those things need to be looked into before we say there was a direct cause or root cause.”

While it’s unclear what caused the operator to run the red signal, the problem has been a persistent one for the agency and has been cited by the safety commission as an area that needs renewed focus, including in a report at its recent meeting. The derailment also is the second significant incident in less than a year — that last involving a train operator who violated an all-stop order and collided with a stationary train.

In Tuesday’s incident, 32 passengers were onboard Train No. 108, which was headed to Glenmont when it derailed at about 11:20 a.m. as it was pulling out of the station, Metro spokesman Dan Stessel said. All riders disembarked the derailed train onto the Silver Spring station platform, he said. The first two cars had left the station, and the train was moving at a low speed, Stessel said.

The first car probably “slipped” from its tracks as the train began moving, jamming one car door, said Pete Piringer, spokesman for Montgomery County Fire and Rescue Service, which responded to the scene.

Most passengers, located in the rear of the train’s eight cars, walked out and onto the adjacent platform on their own, while fire crews helped the train operator and another passenger exit a car with jammed doors, Piringer said.

Service was suspended between the Takoma and Wheaton stations. Metro official said they expect service between Takoma and Wheaton to be restored by Wednesday morning.

The shutdown added to an already troublesome morning. Metro had already suspended service between the Van Ness and Dupont Circle stations because of early morning flooding after overnight storms. Service to those stations was restored early Tuesday afternoon.

Investigators from Metro and the Washington Metrorail Safety Commission, which oversees rail safety, were on scene, studying the wreck and pulling video from the 7000-series train, Metro’s latest model, which is equipped with front and rear-facing cameras. The train’s operator underwent drug and alcohol testing as federal regulations require after all incidents, and he is being held out of service until the investigation concludes.

Preliminary information did not suggest any mechanical or infrastructure problems as factors in the crash, Metro said.

“While the investigation is ongoing and all factors will be reviewed, current information does not indicate any conditions or failures related to infrastructure or equipment,” Stessel said.

As part of the investigation, the safety commission will check for track damage, inspect switches and rail cars and ensure all necessary evidence, including photographs and measurements are collected before Metro is allowed to “re-rail” the cars and move the damaged train off the track. Metro did not know what if any damage had occurred to the cars, which cost about $2 million each.

Investigators will record measurements, download data, review camera footage and look over inspection and maintenance records before releasing a conclusive ruling in a few months. They want to determine whether the operator made a mistake by moving through the red signal or if he was given permission to move by the Rail Operations Control Center, which can occur in extenuating circumstances, Smith said.

According to preliminary information from the safety commission, it appears the first car of the train entered a center storage track, known as a “pocket track,” while the second car “appears to have continued moving in the direction of Glenmont.” The pocket track was already occupied by an out-of-service train. The front set of wheels on the second car derailed, according to the commission’s preliminary statement, causing the second car to make contact with the first car.

Pocket tracks are used to move trains off the main tracks briefly for things such as track maintenance or to turn them around.

The derailment was the second significant event for the transit agency in less than a year.

Operator error was cited as the cause of an October collision that resulted in about $12 million in damage when an empty, out-of-service train struck a stationary train while the system was under a zero-speed command. The command means the operator should stop their train and remain stationary.

The safety commission determined last month that the operator of the striking train, who had a lengthy record of red signal and other violations, including a suspension for a previous crash and a derailment, had disobeyed a stop command for reasons that remain unclear. Investigators said cellphone records also indicate the operator’s phone was in use at the time of the crash, in violation of policy.

David L. Mayer, chief executive of the safety commission, called the October collision Metro’s “most significant” safety event in years and said it underscored long-standing, unaddressed issues that the transit agency needed to correct immediately.

That operator was fired after the crash. But the incident prompted the safety commission to order Metro to install a “mode awareness tool” in all trains that reminds operators to remain stopped when halt orders are issued. Metro officials have also said they are searching for a way to gain more direct control of trains during zero-speed commands to cut down on signal and moving violations, reduce human error and provide greater security to passengers against collisions.

The last Metro train derailment was Jan. 15, 2018, when a broken rail caused a Red Line train carrying 61 riders, the operator and a Metro Transit Police officer to leave the tracks and skid 1,200 feet in a tunnel outside the Farragut North station. No one was injured.

However, agency records show at least nine derailments of maintenance vehicles such as hi-rail vehicles — large utility trucks that can drive on roads and rails — over the past two fiscal years. The safety commission has cited the transit agency for a worrisome number of incidents where operators have run red signals and violated zero speed commands.

“We have had findings and concerns about other red signal overruns,” Smith said.

Metro records also show that red signal overruns have increased from 10 in all of fiscal year 2019, to 12 in the first three quarters of the last fiscal year, with a marked increase beginning in spring 2019. In November, Metro created an in-house committee to determine what was causing increasing overruns and vehicle movement violations.