WASHINGTON A group of key U.S. House Democrats introduced legislation on Friday to authorize $547 billion in additional spending over five years on surface transport, a plan that would mostly go to and bridges and increase funding for passenger rail and transit.   House of Representatives Transportation and Infrastructure Committee Chairman Peter DeFazio said in a statement the proposal seizes on a once-in-a-generation opportunity to move our transportation planning out of the 1950s and toward our clean energy future.