Replica of 1829 locomotive Marc Seguin at the Champs Elysées Expo Train Capitale, Paris, 2003.
Shortly after the Stockton and Darlington Railway in England opened (1825) he visited it and observed George Stephenson's Locomotion in operation. In 1829, he delivered two steam locomotives of his own design to the Saint-Étienne–Lyon railway. These used an innovative multi-tube boiler and also prominent mechanically driven fans to provide draught on the fire, rather than the blastpipe that was coming into common service at this period. This boiler resembled the later Scotch marine boiler in some aspects, in that the boiler had a large single flue from the furnace, then many small-diameter firetubes returning to a chimney above the firebox door. Uniquely, Seguin's design also arranged the furnace in a large square water-jacketed firebox beneath the boiler to provide a large grate area and greater heating capacity. Robert Stephenson had also made the same decision with his Rocket, but placed his firebox separately and behind the main boiler shell. Seguin's boiler enabled steam-engine trains to increase power and velocity from 4 miles per hour to 25 miles per hour making railroad a more viable mode of transportation.
Inventor but also entrepreneur, teaming with his brothers, Camille, Jules, Paul and Charles, as well as his brother in law Vincent Mignot he continued his father's successful business in textiles, paper, gas-lighting, coal mines, construction and added to it a railroad company and a bridge construction business.