Complex sentence: It opened in stages between 1846 and 1850, and on completion of its line it merged with the Glasgow, Paisley, Kilmarnock and Ayr Railway: the combined company took the name "Glasgow and South Western Railway" (G&SWR).
Split into simpler sentences: It opened in stages between 1846 and 1850, and on completion of its line it merged with the Glasgow, Paisley, Kilmarnock and Ayr Railway. The combined company took the name "Glasgow and South Western Railway" (G&SWR).