underpass at Alewife

Used primarily for buses on northeast side of Alewife station under Rt 2. Was this part of Freight Cutoff?

The alignment was part of the Fitchburg Cutoff/Freight Cutoff. However, the older bridge over the rail line was replaced with the modern concrete arch in 1984, in preparation for the reconfiguration of the 2/3/16 rotary to the north the next year.

As a frequent user of this I believe it is the primary exit for all traffic (a lot more cars than buses) from the Alewife station to Route 2 westbound and Route 16 eastbound.

Hard to believe that the B&M was still running several through jobs per day through that area right up until the mid 70's.

That must have been an interesting area between the Fitchburg, the Cutoff and, The Lexington Branch.

Was there ever a tower in that area?

Not that I know of . As a past resident of Arlington (1958-1984) , occasional railfan and extensively employed in the construction of the Red Line extension from Harvard to Alewife, there was never a tower near Alewife. West Cambridge Yard, the Lexington Branch and the interlocking near Brighton St , Belmont (formerly Hill Crossing) area was under the control of Waltham Tower. I don't remember where the dividing line with the B+M towers to the east was.

What oversite (if any) did the North Cambridge - Mass Ave tower have over the Cutoff?

AFAIK the tower in Davis Sq. only controlled the crossing gates. So I'd guess that a tower at Mass. Ave would have done the same job. Where the Freight Cutoff crossed the Lexington Branch was called 'Diamond Crossing' in a 1947 ETT, later 'Fens Crossing'.

In 1947, 'Signal Control System' (CTC) was in effect between Hill Crossing and a northward dwarf signal 1300 feet past North Cambridge (Mass. Ave) and it was bi-directional. From the dwarf to 1,000 feet south of Somerville Jct. it was an Inward Main Track, no train orders required. Outward trains were only allowed with pilot protection or full flag protection. Later the CTC was extended the whole length.