WASHINGTON — Crumbling railroad ties allowed Metro tracks to spread too far apart leading to Friday morning’s derailment near the East Falls Church Station, according to preliminary findings from Metro’s internal investigators.

Metro said Monday that tracks across the system are receiving a special round of inspections to ensure that any similar problems are immediately addressed. Metro also said it inspected the interlockings that are seeing heavier use due to the current track work on the Red Line before the system opened Monday morning. Additional inspections are planned throughout the system.

In the case of Friday’s derailment, Metro said in a statement that contributing factors “including car equipment, weather, temperature and other factors remain under review.”

Metro said there is no evidence of train operator error.

About 75 passengers were onboard the train when it derailed shortly after 6 a.m. as it approached the station.

No trains ran between Ballston and McLean and West Falls Church all weekend as crews investigated the incident, repaired the tracks and inspected the area.

Metro said more than 450 rail ties were replaced in the interlocking area where trains cross from one track to the other.

The switch area is just beyond the stretch of tracks that were refurbished in June and July. The work on the Orange and Silver lines was part of Metro’s accelerated repair plan that is targeting 15 areas of the train system that need the most repairs and maintenance. The ongoing project will close single tracks or entire stretches of the system for several weeks at a time. Work is set to wrap up next spring.

Tracks that were too far apart also caused a derailment near the Smithsonian Station last year. In that case, investigators said track inspectors should have spotted the issue, and a track inspection vehicle’s warning was deleted.