Complex sentence: The only line that appeared to be well positioned was a proposed branch of the Grand Junction Railway (GJR) out of Belleville As the new mining areas were directly north of Trenton and Belleville, the PERC was also in an ideal location as a starting point.
Split into simpler sentences: The only line that appeared to be well positioned was a proposed branch of the Grand Junction Railway (GJR) out of Belleville. Since the new mining areas were directly north of both Trenton and Belleville, the PERC was also in an ideal location as a starting point.