U.S. engineer and ship designer who invented the widely used inverted-T railroad rail and the railroad spike. He tested the first steamboat to use screw propellers, built by his father, the noted inventor John Stevens. He also assisted his father in the construction of the “Phoenix,” on which he served during the steamboat's historic ocean voyage from New York to Philadelphia in 1809.

Stevens became a prominent figure in naval design. He developed a “false bow” for the steamboat “New Philadelphia,” which increased its speed so that it was able to leave Albany, N.Y., in the morning and reach New York City before nightfall. In 1822 he built the ferryboat “Hoboken.”

Stevens designed the inverted-T rail in 1830; he found that rails laid on wooden ties, with crushed stone or gravel beneath, provided a roadbed superior to any known before. His rail and roadbed came into universal use in the United States. He also added the pilot, or cowcatcher, to the locomotive and increased the number of drive wheels to eight for better traction. In 1846 Stevens, an ardent yachtsman, designed the “Maria,” for 20 years one of the fastest yachts in the world.