Rockville Bridge is located a few miles north of the city of Harrisburg. The 3800' bridge completed in 1902 for the Pennsylvania Railroad links the East-West shores of the Susquehanna River.
Fellow rail fans can often be spotted with their cameras on either shore. There is also a recently completed inn on the West shore where the lodgers can comfortably sit on the deck and watch the action.
My absolute favorite spot at the bridge is from the seat of a kayak in the center of the river near a small island just South of the bridge. This treed island can be seen in the lower left corner of the June 2015 Trains magazine cover photo and from a kayak seat in the below photo.
Weekdays in August and September are the most enjoyable, when the river is clear, low and slow. A cooler with a foot long Subway sandwich, chips, bottled water and camera are all that is needed for several hours of train watching here. This is a very tranquil place, rippling waters, many birds, a quarter of a mile from the noise of either shore only to be interrupted by the sound of approaching locomotives.
Witnessing two trains on the bridge at the same time is not unusual. In the photo below I tried to time my shot so the Amtrak locomotive on the North side of the bridge appeared to be pulling the freight train that was actually passing in the opposite direction on the South track.
The concrete repair work to the spandrel wall of pier 19 just below the cab of the Amtrak locomotive was necessitated by the wall failing under the weight of a passing unit coal train in August of 1997. Four fully loaded 100 ton hoppers were dumped into the river.
The "Pennsylvanian" a daily 9 1/2 hour Amtrak train from Pittsburgh to New York's Penn Station usually crosses the bridge a few minutes before it's 12:55pm stop at the train shed of Harrisburg station.
A few years ago on my way home from a day at the bridge I happened on a rare sight today, a caboose on the bridge. I had to stop and get a photos of that!