Air Force One is one of the most recognizable and most mysterious planes flying today, specifically designed to securely shepherd the President around the world. Things used to be a lot different 75 years ago when Franklin. D. Roosevelt was riding around on a bulletproof train.

The latest video from Tom Scott on YouTube features Ferdinand Magellan, later designated US Car Number 1, which is the heaviest American railcar ever built, specifically for presidential travel.

The train was built to be exactly 285,000 pounds, which was the weight limit of a railcar designed for the rail system at the time. A large section of the car features bulletproof steel plating and three-inch thick glass.

There are also two escape hatches in case the train ever crashed or came under attack. The first is a removable plate in the bathroom wall, and the second is a submarine-inspired rooftop hatch, for a situation where the train car was knocked on its side.

It’s the train President Truman ran his reelection campaign on, and where the famous photo of him holding up the wrong election day newspaper headline was taken.

But FDR was the first sitting president to ever travel by air, and it didn’t take long for the railcar to be decommissioned as flight became significantly more timely and practical.