Let me try and clear up a bit of "confusion"about EAST Commercial St,the "bridges" over the Back Cove area,and the "original" trackage in that area. First,the highway bridge(Tukeys Bridge to us old timers in the Greater Portland area) was built by the Tukey family as a TOLL bridge in the 1700s,when Portland was called Falmouth. I guess they didnt maintain this vital road link to the east very well,and the Mass. General Court(legislature) nor the "Falmouth" selectmen didnt do too much(Maine was part of Mass. until 1820).So,"the locals" took law into own hands,and made the bridge "public" after beating up the Tukeys! Private,toll charging turnpikes and bridges HAD to be maintained according to the laws. Then the Grand Trunk built the train bridge across the entrance to Back Cove in the late 1840s as they built towards Canada. BOTH bridges were "draw spans"(including the last Tukeys Bridge done in 1919(before I-95 in the 1960s). Ships and Barges would bring clay to the "Pottery & Sewer Pipe "works,coal yard and trolley power house on what is now Forest Ave,about where Hannafords Shop/Save is now,until the Cove silted up in the 1930s. The Portland & Rochester,with its yards & station in the Bayside area,built a connecting railine around the approach to Tukeys bridge on the south side,and linked up with the Grand Trunk at the western approach to the rail bridge,calling it Portland Junction. This lasted 1870s to 1947. The P&R even used to run a shuttle train,with "tank engines" to get passengers from their station at the foot of Preble St. over to the Grand Trunk station on India St(and this even lasted a few years after Union Station was built in the 1880s,using the present,but out of service,"Union Branch" alongside the Interstate & Ball Park. This area was really developed after W.W. Two,into Yard 7 of the Portland Terminal Co.,and EAST COMMERCIAL ST. even got a paving job,around where the Sewer Plant is now:there was also a dump in the area,and a coal yard,whose pilings can be seen to this day. ALL of the warehouses were built WEST of Tukeys Bridge,in what was a ball field & circus grounds.By the 1950s, "2"Portland Terminal switchers were serving these warehouses,junk yards,besides the "flagship consignee",A&P stores warehouse,built on the site of the P&R yards in the 1920s. By the mid 60s,many warehouses there had moved/shut down,and business dwindled to "1" crew a day. The further filling in of Back Bay in the later 1960s,to build the Interstate,further altered the area. A map of Portland,say from 1900 to 1950,will really show the OLD alignment. Hope this helps a little. Bud