From Wiki: The IBM 1401 is a variable wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing unit record equipment for processing data stored on punched cards and at providing peripheral services for larger computers. The 1401 is considered to be the Model-T Ford of the computer industry, because it was mass-produced and because of its sales volume. Over 12,000 units were produced and many were leased or resold after they were replaced with newer technology. The 1401 was withdrawn on February 8, 1971.
Nowadays there are still several of machines like these operational. For example in the Computer History Museum in Mt. View, California. The people who used to operate these machines are mostly retired now like Ken and Paul in this introduction video. It’s a great video, you should have a look at it. Now what I found very interesting is a recent fun project by enthusiasts, that had no particular practical use, except for fun. The project took three years but it was successful. As a bit of a nerd myself I had a huge nerdgasm watching the video below when you click the “Read More” link.