Sentence:  Along the UP Trail, America's original transcontinental, mention of the 800's will long recall the capable, long-legged <WSD>Northerns</WSD> that were built for standard-weight limiteds but often doubled for diesels on the "City" streamliners. 
Meaning of the word marked with <WSD> tags:  a steam locomotive of the 4-8-4 wheel arrangement. (4-8-4)