The NS Mon line is the NS branch that stretches from Pittsburgh through Clariton, Shire Oaks yard, Monongahela, and ends in West Brownsville PA. Well anyway here’s my advice on it. Clariton has a few spots, but I am not A fan of fanning there. West Elizabeth has a public grade crossing near the rt51 bridge to Elizabeth. Shire Oaks is completely inaccessible so don’t try it. There Are several pull off spots on the left hand side of the road that are usable for photography. Where the Mitchell power plant was, there is a crossing with a small parking area people use for fishing parking. A bit down from there is Tubby Hall park, where there is a huge parking lot right next to the track. Monongahela has the aquatorium, where there is a fence, but you can still get shots by the NS offices. Apparently West Brownsville yard is completely viewable. Reasons to railfan the mon line- very busy(30-40 trains a week), 19 of the heritage units have been through here. Former PRR line. Mix of different types of locomotives. Union railroad is in Clariton, as is CSX on the other side of the river, and the Wheeling and lake Erie is in Speers.