As MBTA readies to re-start the Orange Line and the northern end of the Green Line, it gets ready to shut the D Line

Some of those charter buses will still come in handy later this week, when the T shuts down the Green Line's entire D branch for a total of 27 days over the next six weeks or so.

The shutdowns, in three nine-day increments, are to upgrade the tracks and to install equipment along the line that is supposed to stop trolleys from crashing into each other.

The MBTA reports the first nine-day shutdown starts Saturday and runs through Oct. 2, followed by another shutdown from Oct. 8 until Oct. 16 and then a final one from Oct. 22 until Oct. 30.

More than a mile of track will be replaced, mainly between Eliot and Riverside.