A fire at the SIlver Spring Metro stop. Photo by Catherine Merwitz.

Investigators are still going through the debris left by the fire underneath a Red Line train at the Silver Spring Metro station that crippled last night’s rush hour, but they have ruled out that fault for the blaze is on track conditions.

The train, which was unloaded at Takoma following a report of smoke in one of the cars, started emitting smoke and flames shortly after it rolled into Silver Spring about 6 p.m. last night. The train was composed of 1000-series cars, which are the oldest in Metro’s fleet and are due to be phased out beginning next year in favor of the modern 7000-series coaches.

As part of the ongoing investigation, Metro officials are examining every inch of the car from which the blaze erupted. Based on examinations of the fire so far, Metro says one possibility was unintended contact between power cables and a metal hose on the culprit car’s undercarriage.