A group of Norwalk residents was in Hartford Monday to voice their concerns about state plans to build a new $1.1 billion train bridge over the Norwalk River.

Members of the organization Norwalk Harbor Keeper filed a 27-page lawsuit three months ago in federal court against the Department of Transportation, challenging the failure of the state to conduct an adequate environmental review of the project.

The group says that the state wants to construct another movable bridge like the Walk Bridge currently present, but they say that would be too expensive.

They also say the 120-year-old bridge has been stuck open several times over the years, disrupting the 200 trains that cross it every day.

The DOT told News 12 in a written statement that it evaluated about 70 bridge designs before deciding that the best alternative was a 240-foot vertical lift span. It says that because the Norwalk River is a "navigable waterway" under U.S. Coast Guard regulations, the bridge must be able to accommodate marine traffic below. The agency also says a new movable bridge is the only answer.