This photo is from 1973 and shows part of the Tower X control board with FX in all its former glory. Doug Kydd photo. The shot of BO-1 would be a hair to the left of the seam between the two left panels.From NErail. . .
Backup shove move by Pan Am job BO-1 of 13 empties returning from Rousselot Gelatin in Peabody onto the Yard 21 tracks on Tuesday. Peabody loads amongst the most frequent visitors to Yard 21 because on days when BO-1 runs as far as Peabody it often has trouble finishing its work within crew hours (presumably these empties were dropped in Salem or Everett at the end of the previous day's shift for a fetch at beginning of next day's trip).
Pic taken from FX interlocking (see dwarf signal lit up in the background). Curved track on the left foreground of the photo is the end of northbound leg of the freight wye tying into FX interlocking at this spot underneath the Leverett ramp decks, and the track snaking under the highway decks in the background past the signal is where all the freight + work tracks framing the backside of Boston Engine Terminal cross over to the outbound Eastern & Western Route mains. The big Keolis tie/rail piles off to the left of the photo frames the perimeter acreage between FX and the industrial backlots of Roland St. in the Innerbelt. This vantage point is about 650 ft. inbound of the Sullivan Station platforms. The empty hoppers on the rear half of the train past the last highway truss abutment have all cleared the switches and are traveling on the Yard 21-proper trackage.
For those interested: Right to left is Everett Jct, Draw 7, Reading Jct, FX.