The Economic Times

In 1891, engineers built a railway up a Colorado mountain too steep for normal trains; its toothed track still carries passengers to the 14,115-foot summit

Engineers developed a unique cog railway for Pikes Peak's steep inclines. This innovative system allowed trains to climb slopes ordinary railways could not manage. The Pikes Peak Cog Railway began operations in 1891, carrying millions of passengers safely. Technology has modernized the line over the years, with new trains introduced recently. Its fundamental engineering principle remains unchanged since its inception.