Amtrak Joe is hopping on the bus.

Former Vice President Joe Biden is hitting the road for the most intense campaign swing of his presidential bid.

Biden launched an eight-day bus tour of Iowa Saturday to shore up his slumping poll numbers in the crucial first-caucus state ahead of its Feb. 3 nominating contest.

Biden continues to hold a lead in national polls — but his campaign fundraising is lagging behind the rest of the top-tier candidates, and his advisers have limited his appearances in recent weeks after a string of gaffes and verbal flubs.

Biden, 77, will cover 800 miles and 18 counties over the coming week and will log up to four appearances a day.

“The goal is to have him connect with people one-on-one,” campaign spokesman TJ Ducklo said. “It is a very close race as we get close to voting … that was always the expectation.”

Biden has been plagued in recent weeks by accusations that his job as President Barack Obama’s veep enabled his scandal-scarred son, Hunter, to reap illicit profits in Ukraine.