WASHINGTON — U.S. Transportation Secretary Elaine Chao called the Gateway Tunnel project under the Hudson River “an absolute priority” even though President Donald Trump’s proposed budget cuts off an important source of federal funding for it. “We have kept a very close eye on this,” Chao told the Senate Environment and Pubilc Works Committee Wednesday. “Gateway is an absolute priority in terms of our focus. We understand what is happening there.” Chao was asked about Gateway by U.S. Sen. Cory Booker (D-N.J.), who earlier joined with Gov. Chris Christie and invited her to tour the existing Amtrak tunnels, which eventually have to be closed to repair damage caused by Hurricane Sandy.