Sentence:  His interest in <WSD>railways</WSD> is not the quality that marks Pearson out. Everyone was interested in <WSD>railways</WSD>. Over a thousand miles of them opened between 1837 and 1845, most of what would become the national network. [...] You needed an Act of Parliament to build a <WSD>railway</WSD>; but that wasn't very hard to obtain if you could give the appearance of adequately funded competence. 
Meaning of the word marked with <WSD> tags:  A track, consisting of parallel rails, over which wheeled vehicles such as trains may travel.