The Union Pacific Railroad introduced the 'Big Boy' class of steam locomotives, the largest and most powerful steam locomotives ever built. These 4-8-8-4 articulated engines, manufactured in Schenectady, New York, were designed to haul heavy freight trains over the mountains of the American West. The 'Big Boys' represented the pinnacle of steam locomotive technology, a final flourish before the diesel era.

The 'Big Boy' locomotives are a testament to American engineering and ambition, themes that have been explored in American poetry and literature. These massive machines, symbols of power and the conquest of the continent, have inspired poets who write about the American landscape, industry, and the myth of the frontier.