STATE HOUSE NEWS SERVICE

THE MBTA lifted an end-to-end speed restriction on the Mattapan Line trolley early Thursday morning, but there’s still no official timeline for ending mandatory slowdowns across the entire Green Line and pockets of the Red, Blue and Orange Lines.

The agency announced on Twitter shortly before 7 a.m. Thursday that it replaced a “global” speed restriction on the Mattapan Line, which links the Red Line’s Ashmont end point with Mattapan, with “block restrictions where necessary.”

That’s the only major progress officials have announced in several days, after telling reporters last Friday that they slowed trains down out of an “abundance of caution” and while they worked to verify that track inspection, necessary fixes, and safety checks have been made.

All Green Line trains must still operate at slower-than-usual top speeds, and MBTA leaders have not indicated whether they have been able to lift any of the patchwork speed restrictions that on Monday affected nearly a third of the combined Red, Orange and Blue Line tracks, nor how much longer riders will need to endure the disruption.

While Gov. Maura Healey has repeatedly pledges more transparency from the MBTA, a transit authority spokesperson declined to answer questions Thursday about the status of the remaining lines.

MBTA Interim General Manager Jeff Gonneville said last Friday that the T had six inspection teams in the field who would go line by line to confirm it was safe for trains to travel at maximum allowable speeds. He asked riders to “allow us into the start of service on Monday” — now three days ago — “to validate repairs and verify speeds.”

The widespread mandatory slow zones, announced and ordered the evening of March 9 after MBTA officials determined they did not possess sufficient documentation to prove they fixed previously identified track defects, continue to saddle riders with sluggish, less reliable and more crowded trips.

The Department of Public Utilities, which serves as the state agency responsible for MBTA safety oversight, inspected a section of Red Line track on March 6 and observed concerns with the quality of the tracks. On March 7, DPU Rail Transit Safety Director Robert Hanson sent MBTA officials six letters ordering corrective actions. On March 9, the MBTA implemented a systemwide slowdown, then replaced universal speed restrictions with a vaguely defined patchwork on the Red, Blue and Orange Lines the following morning.

Train data tracked by advocacy group TransitMatters estimate that on Wednesday, an end-to-end round trip on the Red Line featured 68 minutes of total delay, by far the worst impact of the three heavy rail lines. TransitMatters data show nearly 17 minutes of total round-trip delay on the Orange Line and more than 10 minutes of delay on the Blue Line.

Friday will also mark exactly nine months since the MBTA slashed weekday service on the Red, Orange and Blue Lines due to the safety risks created by a shorthanded dispatcher workforce. At the time, officials said the cuts were temporary and would be reversed once the T hired enough dispatchers, but higher-ups have moved the target in recent weeks and now say any decisions to restore frequency will depend on vehicle availability and driver staffing.