* It's not clear to me that this occurred at a legitimate RR crossing, or near one, so there's no assurance that signs saying how to contact the railroad were close enough to be useful in time. The article says "in the area of Route 30 and Railroad Avenue", and that doesn't tell us anything very enlightening.
A look at the satellite image (N 40 0' 25" W 76 6' 56") indicates there are no crossings in the area - it's all grade-separated former Pennsy not far from the Strasburg interchange. Which would lead me to believe the horse simply spooked and ran onto the ROW.
Route 30 passes over the ROW, and Railroad Ave simply runs parallel to the ROW for a short distance.