Only one year later at Erie Railroad, May 1, 1850, Kirkwood was succeeded by Charles Minot, and became Chief Engineer of the Missouri Pacific Railroad. the Pacific Railroad, and was responsible for the construction of the road from St. Louis to Pacific, Missouri. The towns of Kirkwood, Missouri, and Kirkwood, New York, are named after him. Late 1860s he consulted on and completed the Bergen Tunnel in 1858–9. At this time he was Engineer of the Brooklyn Water Supply, whose successful completion was largely due to his efforts.