BOSTON (CBS) – After a June derailment that knocked out the signal system, the MBTA is expecting parts of the Red Line to return to normal by Aug. 15.

According to MBTA officials, the repairs will create a five-minute improvement in travel time on the core of Red Line.

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The Braintree and Ashmont branches will continue to experience delays.

A train derailment at the JFK/UMass station on June 11 severely damaged the line’s signal system.

An MBTA Red Line train derailed just outside the JFK-UMass station Tuesday morning. (Photo credit: Boston Fire Dept. )

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The signal system controls the speed and frequency of Red Line trains and is part of coordinating the dispatch of trains through the JFK/UMass area where the Ashmont and Braintree branches merge.

Without a fully functioning signal system, Red Line trains are traveling through the affected area under a manual process involving approximately 50 people. The signal bungalows, which control the signal system, were damaged in the derailment.

According to the MBTA, typical Red Line service involves 13 to 14 trains per hour. Following the derailment, six trains were running per hour. That has since been updated to 10 trains during rush hour.

The MBTA said its crews and contractor personnel have been working seven days a week to make repairs to signals, communications, and power infrastructure to improve service.

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MBTA fares increased July 1.