Daniel Callahan was born in Ireland in 1830. He came to America in the 1840s and by 1845 he was already working on the construction of railroads. About 1850 he met W H McDowell, a railroad contractor two years his senior. They quickly bonded and became close business partners. They built railroads together in Pennsylvania, Maryland, Florida, South Carolina and Georgia before the War Between the States broke out. Callahan joined Claghorn's Chatham Artillery based in Savannah, Georgia and within a year became a railroad builder for the CSA Army while McDowell became the South's bridge and trestle superintendent. In December 1864, Callahan built the causeway across the back channel of the Savannah River to allow the Confederate Soldiers to escape Sherman's advances. After the War, McDowell settled in Wilmington, NC, while Callahan stayed in Savannah. In the next ten years he rebuilt several railroads in Georgia and South Carolina and constructed all of Savannah's street and suburban lines. While traveling to Charleston, SC on business, Callahan met William T. McNelty, a seasoned steamboat captain. The fellow war veteran liked Callahan and most likely introduced him to his youngest sister, Margaret Jane McNelty. They were married in Charleston on August 11, 1870 at the home of her mother, Jane Taylor McNelty. Eight months later W H McDowell would die in Cincinnati while finishing the Newport and Cincinnati Railroad bridge. In the following decade he continued to lay many miles of track in the Carolinas, Maryland, Georgia, Alabama, Florida and Tennessee. In 1876 they moved to Tennessee to be closer to his work but while in Nashville, Margaret became ill. They rushed back to Charleston where Margaret sadly passed away in November, 1879. She was buried in Magnolia Cemetery, Charleston, SC, next to her mother and sister. In the 1880s, Callahan traveled to Mexico (1880-81), Guatemala (1884-85), and Panama (1885) to build railroads in those fledgling countries. Between those trips he called Rome, Georgia home, building its street lines and regional railroads. His near fatal fall down a flight of stairs in Atlanta (April 1884) and detainment in Panama during General Barrios' uprising (March 1885) did not slow him down. By 1885 he was traveling to New York City frequently, investing his money in railroads and race horses. He returned to Honduras to build railroads at least twice in 1890 but traveled back to NYC in December 1890 when his health began to decline. After a six week stay in a NYC hospital, Daniel Callahan died. He was buried in Mt. Olivet Cemetery in Chattanooga, TN, next to his partner, Thomas Redmond's family plot. There is no grave marker where Daniel Callahan is said to be buried.