Bay Colony RR completes Millis trackage rights deal w/ MBTA

Per STB filing, MBTA and Bay Colony RR have successfully concluded trackage rights agreement governing operations on the Millis Industrial line. Does this mean the sad and wobbly track will now get much needed upgrading?

http://www.stb.dot.gov/filings/all.nsf/ ... enDocument

well, on the line to Newton, I wouldn't expect much trackwork for a few cars a month...

So, what's the background on this? The STB document basically says that the MBTA has withdrawn its termination of Bay Colony's right to operate on the line and negotiations will follow. Why did the T want to make them go away? What are the "issues" that are referenced but not explained?