Sentence:  About 1888 J. E. McNaughton of Barnumville and E. G. Bacon became proprietors of the `` Green Mountain Telegraph Company '' , connecting all offices on the Western Union <WSD>line</WSD> and extending over the mountain from Barnumville to Peru , Londonderry , South Londonderry , Lowell Lake , Windham , North Windham , Grafton , Cambridgeport , Saxton 's River , and Bellows Falls . 
Meaning of the word marked with <WSD> tags:  a conductor for transmitting electrical or optical signals or electric power