Michael Portillo starts his railroad journey across America at New York's Grand Central Terminal. There he boards the Manhattan subway system, the busiest rail transit system in the US. He learns about Manhattan's iconic skyscrapers, hears tales of the dodgy industrialists of yesteryear known as 'Robber Barons' and visits the new transport hub close to the site of Ground Zero.

From Manhattan, Michael Portillo travels east to Long Island. Beginning in Brooklyn, he hears the moving story behind the construction of the world's first steel suspension bridge. Below ground, he investigates the city’s first subway and the dangers faced by the sandhogs who built it. In Long Island, he relives the Roaring Twenties before ending his journey at the Montauk lighthouse.

Michael Portillo travels along the Hudson River through New York State. Beginning at Penn Station, he hears from Amtrak's police chief how railroad policing tackled notorious train robbers such as Butch Cassidy and the Sundance Kid. At Tarrytown, Michael is spooked by a famous ghost story. In Albany, he samples Albany Ale before rubbing shoulders with the state senator.

Continuing his travels west through New York State, Michael Portillo has a lightbulb moment in Schenectady, when he discovers how Thomas Edison's General Electric Company led the way in modern rail technology. A yellow brick road beckons him to Chittenango, where a Kansas farm girl introduces him to a lion and a tin man. He then braves the awesome power and drenching spray of Niagara Falls.

Michael Portillo travels to Philadelphia, feasting on a gargantuan Philly cheesesteak, then pays homage to one of the city's most famous sons, Rocky Balboa. In Traintown USA, he rides on a vintage steam locomotive. Next stop is the 'sweetest place on earth', where Michael learns about the world's largest chocolate factory. His last stop is Gettysburg, the most famous battlefield of the Civil War.

On the Mason-Dixon line, Michael Portillo discovers the origins of what became, for black Americans, the border between slavery and freedom. He uncovers the explosive history of gunpowder in Delaware and then travels to Baltimore, home of the first railroad in the US. At Fort McHenry, he hears how the Star-Spangled Banner was born and learns what makes a Maryland crab cake so delicious.