Trains are running again on the Red Line, but MBTA officials warn that travel times will continue to be longer than usual for the foreseeable future because of significant infrastructure damage caused by Tuesday's derailment.

General Manager Steve Poftak said Tuesday that signal bungalows near the JFK/UMass stop were damaged by the derailed train, and in a Wednesday series of tweets, the official MBTA account said that crews stationed along the tracks will need to direct traffic manually until the system is repaired.

As a result, trains that serve passengers on a line that runs from Braintree through Quincy and Dorchester and into Boston Cambridge and Somerville will move more slowly than usual, and electronic countdown clocks will remain inactive across the Red Line.

Read more: Second Derailment In 4 Days Turns Heat Up On MBTA

"Looking ahead, bungalows will need to be rebuilt, new signals & cables installed, tracks repaired. At this time, we can't say how long that will take," the MBTA wrote. "For now, trains will continue to travel at slower speeds. We ask customers to allow extra time & use all available services."

An MBTA spokesman said Wednesday that there is still no estimate of what full repairs will cost.

Shuttle buses replaced Red Line service between North Quincy and JFK/UMass for part of Wednesday to allow for maintenance work, but trains began running in both directions by 1:45 p.m.

Tuesday's derailment was the second on the MBTA's passenger lines in less than a week and the fourth this calendar year. In response, officials hired LTK Engineering Services to conduct an outside review of all derailments in the past two years.

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The MBTA wrote that "bungalows will need to be rebuilt, new signals & cables installed, tracks repaired."
Courtesy/Jacquelyn Goddard/MassDOT via State House News Service