Complex sentence: However, the LNWR gave up its share of the lease on a line that was isolated from the rest of its system when it expired, and the Midland was relieved of the necessity of extending from Wirksworth over a very difficult piece of terrain.
Split into simpler sentences: However, the LNWR gave up its share of the line-it was, after all, remote and isolated from the company's main system. The Midland was therefore relieved of the necessity of extending from Wirksworth over a very difficult piece of terrain.