Delays of 10 to 20 minutes on the Red Line will continue through the summer because of challenges repairing signal infrastructure in the wake of a derailment earlier this month, MBTA officials said Friday.

Standing before reporters with a table full of damaged equipment, MBTA General Manager Steve Poftak said the transit authority would run fewer trains than a typical rush hour and need to use crews to manually direct traffic "at least through Labor Day."

The June 11 derailment near the JFK/UMass station completely destroyed one bungalow housing signal equipment and damaged two others, and Poftak said the repairs will take additional time.

"It is a very complicated process," Poftak said. "Some of this equipment is not the kind of stuff you'd buy off the rack."

Investigators still have not determined a cause of the derailment, but have ruled out operator error and foul play and are now looking at whether the 50-year-old car or its wheel truck from 2014 are responsible.

All 68 other Type 1 cars in regular service similar to the one that derailed underwent additional inspections in the wake of the incident, officials said.

~ Chris Lisinski/SHNS