Step 1 : Introduction to the question "6. By which transit company was the Franklin Av. Shuttle built?"
...1. IRT 2. BMT 3. IND 4. MTACC The Franklin Av line was actually originally part of the BMT Brighton local track. The first BMT Brighton local service was connected to Franklin Av on the Franklin Av El and ran from one of the either of the old BMT terminals, Park Row across the Brooklyn Bridge, or the Fulton St Ferry in Brooklyn. I can't find any proof that any such dual routes existed, but the tracks suggest that intended routes included local service from Coney Island to Franklin Av and express service making Brighton express stops and then running along Flatbush Av and over the Manhattan Bridge. The current day construction is handled by the MTACC or the Metropolitan Transit Authority Capital Construction.