President of the B&O Railroad from 1858-1884. He played an important role during the Civil War, ensuring that the B&O would remain loyal to and perform invaluable service for the United States government. In order to accomplish this, he expanded the shops at Mt. Clare to meet the wartime demand for locomotives, rolling stock, passenger cars, and bridges. Because of their strategic location, the trains and tracks of the B&O suffered major damage during the conflict, but Garrett remained resolute in his support of union forces. His efforts earned the nickname “Mr. Lincoln’s Railroad” for the B&O.
Following the war, he was responsible for continued growth of the railroad. At the time of his death in 1884, President Garrett was operating a rail network of about 1,700 miles, more than triple the mileage of 1865. He oversaw the expansion of both freight and passenger service as all the major railroads spread west, eventually spanning the entire continent. John W. Garrett made sure that the B&O played a central role in the industrialization of America.