Who designed a steam engine more efficient in the 1800s?

In the early 1800s, engineer George Stephenson significantly improved steam engine efficiency with his design of the locomotive, particularly the "Locomotion No. 1" in 1825. His innovations included better use of steam pressure and enhanced boiler design, which contributed to the development of railway systems. Additionally, James Watt, whose earlier improvements in the late 18th century also laid the groundwork for more efficient steam engines, continued to influence engine technology throughout the 1800s.