Charles River Bridges

These Scherzer rolling bridges carry the MBTA Commuter Rail over the Charles River in Boston. Originally this was the site of a bascule drawbridge for the Boston and Lowell Railroad, built 1835. It was the first movable railroad bridge in the United States.

In 1931 the Charles River bridges were replaced after extensive filling and dredging meant that the channel of the Charles River was relocated further away from North Station to allow the terminal tracks to converge into eight main leads crossing the river. The four new structures were double-track, single-leaf rolling bascule bridges. All four were nearly identical in design, varying only in their length and the degree of their skew, two spans crossing the channel at a slightly greater skew than the others. Two were 87 feet in length and two, 97 feet. Each span carried a single 629-ton overhead concrete counterweight and, operated by two electric motors, was controlled from the second floor of the new signal and interlocking station, located nearby on the north side of the river. The bridges were designed by Keller & Harrington, Chicago, while the steelwork was fabricated and erected by the Phoenix Bridge Company, Phoenixville, Pennsylvania. Today, only these two spans remain.