The midland main line split into two here; the passenger lines to the south, the freight lines to the north. The freight lines were on a lesser gradient and went into a tunnel at the SE end until Sharnbrook summit had been passed.
Graham
OK, but this line is now a 15 mile long cycleway/footpath, though a short stretch has trains running too. The square in question is the site of a layout that has been on the exhibition circuit recently.