The 62-mile project calls for service every 30 minutes during peak periods and every 60 minutes at other times. Speeds would reach up to 110 miles an hour.
Connecticut Gov. Dannel P. Malloy's office projects 1.26 million riders annually by 2030.
"Achieving this milestone means we can complete the design and construction of new track, signal and communication systems, bridge and station infrastructure improvements between New Haven and Hartford and provide an economic boon for the region," Malloy said.
The $121 million will be combined with $174 million in state bond financing. The funding announced on Monday brings to $191 million the federal commitment to the project. In total, $365 million in state and federal funding has been committed to the Connecticut portion of the New England rail system.
Service is expected to begin in 2016, when service aboard 12 trains a day will be increased to 34, or 17 round trips.
Sen. Richard Blumenthal, D-Conn., said that although Congress must figure out how to reduce the federal debt that totals more than $16 trillion, funding for New England high-speed rail should be exempt from spending cuts because the regional rail system promotes economic development.
"There's no question that federal spending has to be restrained but this project is multi-year and multi-use and is a wise use of federal funding to support a critical transportation system that benefits the entire New England region," he said. "It deserves priority."
Malloy, members of Connecticut's congressional delegation and federal and state transportation officials announced the funding in Meriden on Monday afternoon.
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