Couple of clarifications...
1) Eastman acid issues: There are 3 hydrochloric acid tanker incidents I'm aware of that involved Eastman's consist.
-One car leaked in Yard 7 (Somerville/East Cambridge) in the late 90's, a school was evacuated, no injuries.
-Much more recently, a car leaked in Sullivan Station, closing the station for hours. This got anti-hazmat folks' dander up.
-A third HCl tanker derailed in Salem right near the plant. Low speed, no tipping, no leak, but city officials got angry about hazmat concerns and cited the Sullivan incident as ammo for their argument. After that it went to trucks. Eastman still gets the hoppers of bones which usually stop over at yard 8 or trackage near the BET and Sullivan. And yes, Univar in Salem still sees small tank traffic; they used to do much more in the 90's.
2) I saw Guilford switching on the Newburyport line in the mid-90s at the EARLIEST. I was driving on 114 and was arrested by the sight of a big G loco on the trestle overhead. I parked, walked up, ran into and talked to the brakeman about the atrocious condition of the rail, and he said they had already derailed twice (that job, that day). They had a few boxcars and I believe they were for a beer customer a little ways north of the 114 trestle. Just south of that trestle was chemical customer Ventron, who used to get molten sodium cars, but they may have been all done by 1990.
3) Remember that branch lines die off from the extremities back toward the trunk in most cases. The last switcher on the Wakefield branch rolled in the spring of 2001, to the Smurfit Stone container place just north of rte 128. But the line north/east of there had been dead for a long time before that, and probably went in sections as the more distant customers died one by one.
