What was the name of the first steam locomotive to carry passengers on a public railway?

Locomotion No. 1 was the first steam locomotive to carry passengers on a public railway. Built in 1825 by Robert Stephenson and Company, it hauled the inaugural train of the Stockton and Darlington Railway in north-east England on 27 September that year.

The locomotive was originally named Active and was designed by George and Robert Stephenson. Its historic train included coal wagons, the passenger carriage Experiment, and additional wagons carrying passengers, guests, and railway workers. The journey demonstrated that steam traction could operate a public railway carrying both freight and people.

Locomotion No. 1 is sometimes confused with The Rocket, which won the Rainhill Trials in 1829 and helped establish the design principles of later main-line locomotives. Puffing Billy and Blücher were also important earlier engines, but they did not hold this specific passenger-service distinction.

Locomotion continued working for the Stockton and Darlington Railway until it became obsolete. After later service as a stationary engine, it was preserved in 1857 because of its pioneering place in railway history.