in 1863, the dighton and somerset railroad was chartered to build a new line from taunton to somerset (across the river from fall river) via dighton. in 1864, the charter was amended to allow extension north to randolph or braintree. this represented a significant threat to the old colony and newport railway (oc&n) and its existing route to fall river; the oc&n acquired the new railroad in 1865. the oc&n was interested in having a route to the growing industrial city of taunton, which was served by its competitor boston and providence railroad (b&p) via the taunton branch railroad. the line was opened in september 1866; it used part of the 1855-built easton branch railroad (acquired from the b&p at that time) south of stoughton junction, which also gave the oc&n a new freight connection to stoughton. the new railroad passed east of downtown taunton with a station at dean street and crossed the tracks of the new bedford and taunton railroad at weir junction near weir village. the line then ran along the west bank of the taunton river through its namesake towns of dighton and somerset before crossing the river over a man-made causeway and bridge at the north end of fall river.