The Act for the North Midland Railway was obtained in 1836, and Frederick Swanwick became acting engineer. Again, Stephenson, who was wishing to concentrate in exploiting the coal in Leicestershire and in Clay Cross, delegated to him the responsibility for almost the entire work involved in its construction. This entailed laying out of the line, preparing the plans and specifications of all the work, and organising and superintending much of the work The construction of the 72 mile line took four years to accomplish, practically its whole length being on embankments and viaducts or through cuttings and tunnels. The line was opened in 1840.
