The full set of available Diagrams  , digital copies of which were donated by Richard Dean, are now available on the Online Archive. In addition to the Midland's wholly owned lines, they also show Joint Lines including the Portpatrick & Wigtownshire, the Midland & Great Northern, and the Somerset and Dorset. Each Diagram, which is actually a map to scale, also shows other companies' lines within the broad Midland Railway geography and, for the more recent ones, details of the surrounding topography too. Don't forget that when you view the full-size image (on the black background) you can double-click on it, and it will enlarge. You can then also drag the Diagram around your screen.