HAVERHILL — While the train bridge crossing the Merrimack River receives repairs over the next three years, the project will cause few interruptions to train service.
So said state officials who have unveiled the project to strengthen the century-old bridge at the western end of downtown.
The bridge carries trains to the downtown commuter station, which is popular with residents of hundreds of apartments and condos in old shoe factories. Those housing complexes have helped resurrect the city center.
Designers of the bridge project said repairs will happen in ways that will allow trains to use the bridge at their normal times.
“I think it’s a terrific project,” Mayor James Fiorentini said. “One of the biggest things that has helped with the downtown renaissance is the train station. The fact that a commuter can live downtown, leave their car at home and commute to Boston has been very big for us and this (bridge repair project) ensures this will continue, and there won’t be a time when they have to close that bridge.”
Some city councilors have said they fear the old bridge that carries commuter and freight trains over the river each day would eventually collapse. The two-track span is similar in design to one that collapsed in Minneapolis in 2007. Haverhill’s train bridge has been repaired several times in recent years while the MBTA began preparations for a bigger overhaul.
The $60 million project is expected to begin in the fall and be completed by the end of 2016, officials said.
The job includes repairs to the small bridge that crosses downtown Washington Street at the edge of the train station. Officials said there will be minimal interruptions to car traffic during repairs to that bridge over the roadway.
The bridges are owned by the MBTA and used by the MBTA’s commuter rail, Amtrak’s Downeaster that runs between Boston and Maine, and by Pan American freight trains. Daily rail service includes about 36 passenger trains and 10 freight trains, according to MBTA/MassDOT spokeswoman Kelly Smith.
Officials said renovations to the bridges are needed to upgrade train safety and operations. The main sections of bridge were built in 1919, but some of the existing foundations date back to 1839. Design for the rehabilitation is being done by HDR, an engineering firm hired by the MBTA. The work will include repairing or strengthening deteriorated bridge members, reinforcing piers, and cleaning and painting the bridges.
According to a June 2009 summary of HDR Engineering’s inspection, the bridge over the river is safe for freight trains as long as only one crosses at a time and it travels no faster than 5 mph. The report said it is safe for two commuter trains to cross the bridge at the same time and as long as they do not exceed 15 mph. Those restrictions are still in place, officials said. The speed restrictions closely followed the Minneapolis bridge collapse that left 13 people dead and dozens injured.
In 2008, the MBTA inspected the double-track span and rebuilt its deck. The job included replacing about 1,600 bridge timbers, installing walkways and railings across the full length, and laying about 8,000 feet of rail.
City Councilor William Macek, who in the past expressed concerns for the structural integrity of the bridge and a possible failure that would halt train travel over the river, said he is pleased the MBTA plans to begin repairs this year.
“The fact that the state is making this project a priority this year underscores the need to assure safety and long-term viability of the rail bridge,” Macek said. “If the integrity of the bridge is secure, it will mean people and businesses on both sides of the Merrimack will be able to count on using rail transportation without question or concern. I know people who will not use the Haverhill (train) station and instead will drive to Bradford to catch the train to Boston .... They are unwilling to be on a train that crosses the river.
“Once the bridge is repaired, I believe there will be more people using the downtown station, which will ultimately bring more business to the downtown area,” Macek said.
Over the years, the train bridge that crosses the river at the western end of downtown Haverhill has been the source of many calls to police. Signs at both ends of the train bridge warning against walking on it were erected in 1997, after a 17-year-old girl was killed trying to cross the train bridge.
“I’m not a designer, but I asked if they could put up gates, install an alarm system or create a walkway for safety,” Fiorentini said.