Here's some past and present shots of the Dean Street Branch (as the Conrail crews used to refer to this line...):
http://photos.nerail.org/showpic/?photo ... ydate%3A45
http://photos.nerail.org/showpic/?photo ... ydate%3A45
http://photos.nerail.org/showpic/?photo ... 1%3ACSX/NH
http://photos.nerail.org/showpic/?photo ... Bay_Colony
http://photos.nerail.org/showpic/?photo ... Bay_Colony
I don't think the Bay Colony Crews would let the engine sit below Summer Street overnight for threat of vandalism (surrounding neighborhoods not so great from Summer Street south to Weir Junction - - As "D" said, Ventura Grain is the place for tie-up. Perhaps there was a mechanical problem - - maybe even a derailment. There is a section of rail just south of Summer Street that has been known to derail a train.
Around the time I took those pictures of the branch in the early 80s, I watched the train crawl up toward Weir Jct and suddenly stop. No movement for some time. Later in the day, I decided to hop on my bike and ride up to the overpass, there the train sat just south of Summer Street. As I cautiously approached the engine, I saw the engineer resting, eyes closed, feet up. I asked him what was the matter, and he pointed down to the wheels - -off the track. He invited me up into the cab and introduced himself as Edward Smith. He explained they were waiting for a block and tackle to re-rail the engine. "D", have you ever met Mistah Smith? He most likely retired in the mid-late 80s.
Rumor has it (from the local neighborhood kid population that has taken over that age-group railfanning job from myself
) that Bay Colony does operate some nights, too. I fully respect the credibility of this statement from one particular young individual -- he knows his trains, and I know from personal experience that he is paying attention.