The Newtown Square Branch was a branch line of the Pennsylvania Railroad that diverged from the West Chester Branch in Yeadon, Pennsylvania and ended in Newtown Square, Pennsylvania. The rail line is mostly overgrown and few bridges remain, with the bridge over Baltimore Avenue located at the Upper Darby/East Lansdowne border having been removed in 2003. The only known presence of rails is at the junction just west of the SEPTA's Fernwood-Yeadon Station. Through Upper Darby Township the former right of way follows PECO's high tension power lines from Fernwood to the Upper Darby/Haverford border at Lansdowne Avenue and Township Line Road.
Built as the Philadelphia & Delaware County Railroad in 1888, it was taken over by a subsidiary of the Pennsylvania Railroad in 1894. The Cardington Branch to Millbourne Mills opened the following year in 1895. Passenger service ran on the line until it was terminated in 1908 due to competition from the West Chester Traction Company trolley lines.
The Newtown Square Branch consisted of yards at Pembroke just past Fernwood Junction and seven stations. The stations were Garretford, Arlington, Llanerch, Grassland, Brookethorpe, Foxcroft and Newtown Square. Major bridges were at Baltimore Avenue, Naylor's Run, Darby Creek, and Bryn Mawr Avenue.
Service past Grassland station stopped in 1963, and all service on the line ceased by 1981. Rails had been removed from the line by Conrail in 1985, along with most of the bridges. The right of way is still mostly intact, though it is largely overgrown with weeds and trees. In some cases, private business has obliterated portions of the line. There do remain several areas where the right of way is accessible to the public, mainly in Naylor Run Park in Upper Darby Township.
At Darby Road and West Chester Pike, Haverford Township has created a small park and painted two murals to pay tribute to both the Red Arrow trolleys and PRR Newtown Square Branch. It also pays tribute to the "Battle of Llanerch Junction". In the park there are interpative signs that describe the history of Llanerch Junction.