HYATTSVILLE, Md. (AP) — Metro says investigators have determined that heat likely caused rails to kink and led a green line train to partially derail in Prince George’s County.

Metro said Saturday the heat likely caused part of the track to expand and move out of alignment. Three cars derailed late Friday afternoon near the West Hyattsville station. No one was injured, and 55 passengers were safely evacuated.

Television footage from a helicopter showed an outdoor section of track that appeared to be out of alignment.

Metro ordered all of its trains to stay below 35 mph on above-ground tracks through the weekend as a precaution. The transit agency says customers may see delays of 10 to 15 minutes.

Metro service is suspended on the green line between Fort Totten and Prince George’s Plaza.

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