Marshall envisioned linking the farms of the Shenandoah Valley and his Piedmont region at the Manassas Gap with the port cities of Alexandria, Virginia and Richmond, Virginia. Marshall became the president of the Manassas Gap Railroad, which obtained a charter from the Virginia General Assembly in 1850. That year Marshall also sold the home constructed for him and his new wife after their wedding (Carrington) and moved to a farm about a mile away in Markham near the new line). The railway would link Strasburg, Virginia to Tudor Hall (a/k/a Manassas Junction, later renamed Manassas, Virginia), where it joined with the Orange and Alexandria Railroad (O&A), which thus linked the Piedmont and Shenandoah Valley farmers to the ports of Alexandria, Virginia and Washington, D.C. as well as Richmond, Virginia.