Benjamin Henry Latrobe II

Benjamin Henry Latrobe II (December 19, 1806 – October 19, 1878) was an American civil engineer best known for pioneering railway bridges, notably the Thomas Viaduct, and serving as chief engineer for the Baltimore and Ohio Railroad. His innovations in wooden bridges and curved masonry viaduct designs significantly advanced American civil engineering in the 19th century. Latrobe also collaborated with Wendel Bollman, a prominent bridge designer, who contributed to early developments in iron truss bridges. His engineering survey plans for crossing the Allegheny Mountains were later incorporated into legislation guiding the construction of the Pacific railroads, establishing his lasting impact on national infrastructure.

Benjamin Henry Latrobe II was born in Philadelphia, Pennsylvania, on December 19, 1806, Latrobe was the youngest son of Benjamin Henry Latrobe, who, six years previously, had married his second wife, Mary Elizabeth Hazlehurst (1771–1841), the eldest daughter of Issac Hazlehurst, a Philadelphia merchant and business partner for Robert Morris.

Latrobe married Maria Eleanor "Ellen" Hazlehurst (1806–1872) of Altoona, Pennsylvania on March 12, 1833. They had four sons (two of whom survived childhood) and three daughters.

Their eldest son, Charles Hazlehurst Latrobe (1833–1902), moved to Florida, where he married and later joined the Confederate States Army. A civil engineer like his father and grandfather, Charles H. Latrobe later moved back to Baltimore, where he served as the city's chief engineer for 25 years and continued to design public buildings and bridges noted for their beauty. His brother, Benjamin Henry Latrobe, III (1840–1901) became an Episcopal Church priest and rector of the Church of Our Savior in Silver Spring, Maryland.

Latrobe attended Georgetown College in Washington, D. C. and graduated from what was then known as St. Mary's College in Baltimore, Maryland, in 1823. After that, he entered the law office of Charles F. Mayer, a prominent attorney in Baltimore, becoming a member of the Baltimore Bar in 1825. After a short stay in New Jersey, tending to his mother's affairs, he returned to Baltimore in 1830 to practice law again.

Although trained in the law, Latrobe was already an accomplished draftsman and mathematician. In 1830, he left the practice of law and entered into civil engineering. Latrobe read Jean-Rodolphe Perronet's books on bridges in the French language and traveled to Philadelphia to study the bridges there. However, during this period in New Jersey, Latrobe learned about working with the timber business and found that he loved surveying. Meanwhile, his elder brother John, who had been educated as an engineer, changed his profession to law. At that time, he was a junior legal counsel for the Baltimore and Ohio railroad. Through his brother's influence, Latrobe was hired as a rodman on the survey locating the railroad west of Ellicott's Mills.

In 1827, the Maryland General Assembly passed "An Act to Incorporate the Baltimore and Ohio Railroad" and "An Act to Authorize the President, Managers, and Company of the Washington and Baltimore Turnpike Road to Construct a Rail Road from the City of Baltimore to the District of Columbia in the Direction of Washington." Similarly, the Federal government passed legislation to authorize a railroad within the District of Columbia in 1828. This was to be the first rail link to Washington. No progress, however, had been made on this railroad as the Company was busy building the main line to Frederick. But, in 1829, the Chesapeake and Ohio Canal Company obtained two legal injunctions that "...restrain(ed) the (railroad) from constructing the road at all, within the limits of Frederick County." This brought the progress of the main line work to a complete halt, and the focus then became on the Washington branch. In 1831, Jonathan Knight, the Chief Engineer of the road, appointed Latrobe and Henry J. Ranney to locate the railroad assisted by Henry R. Hazlehurst.

In 1834, the legal issues had been resolved to the point that work on the railroad could be resumed in conjunction with the canal company, and Latrobe located the railroad from Frederick County to Harpers Ferry, (West) Virginia.