This article has been edited to correct several errors.



East Lyme -- Amtrak officials said Tuesday that work on the new railroad bridge spanning the Niantic River is about 70 percent complete and on schedule.



Project manager Peter Finch said the three-year, $125 million federal project to replace the 104-year-old bridge is on target to be completed in spring 2013 and could even be finished a little ahead of time.



“There’s more going on than you can shake a stick at,” Finch said in a phone interview.



Since May, when Amtrak marked the halfway point of the project, Finch said workers have been assembling parts of the bridge on barges in Niantic Bay before they are installed.



“We’re started on the steel poles for the catenary wires,” Finch said, referring to overhead wires.



Next week, work will start on the gearbox that will operate the drawbridge, also called a bascule bridge, in same fashion as the Mystic River Bridge.



The main operation house is also taking shape and can be seen by those passing by the construction site.



Crews have also been building the approaches to the bridge as well as infrastructure beneath it.



Finch said that the approach track beds from the west are nearly done.



In December, workers will begin trenching for a submarine cable beneath the bridge that will power the motor as well as the railroad signals.



Also, to assist marine traffic, fiberglass bumpers will be installed in November as a barrier between the channel and the bridge.



The new bridge is 58 feet south of the existing bridge, and will be 15.5 feet off the water, giving it nearly 5 feet more clearance than the current span.



Finch said that the major work in the coming months will be on the approach and lift span, which are scheduled to be completed in March.



Material for the new bridge comes from plants in Chicago, Alabama, New Hampshire and West Virginia.



The project, which began in 2010, has been mostly problem-free.



Amtrak project engineer Bill Drexel said Tuesday that the only complication has been the removal of debris dating to the 1938 hurricane as well as pieces of the original 1891 swing bridge that were tossed aside and not documented.



“Back then they did whatever they had to do to get the bridge open,” Drexel said.



Finch said the eastern end of the Niantic Bay Overlook should be done in November, but will not open until the entire project is complete.



The new bridge should be completely open to trains by November 2012, but crews would still need more time to demolish the old bridge, which has been prone to breakdowns that hamstring rail travel on Amtrak’s Northeast Corridor.



Unlike the ongoing bridge replacement over Stonington Harbor, Amtrak spokesman Cliff Cole said there will no travel suspensions during the Niantic River project.



Amtrak will suspend its New York to Boston service on Nov. 5 at 4 p.m. and resume Nov. 6 at noon, so it can install the new bridge in Stonington.



Cole said that is not necessary in Niantic as trains will be able to use one track each on the new and old bridges.

