Tuesday, October 18, 2011

51 Rockville

In 1902, the Pennsylvania Railroad completed a new bridge across the Susquehanna River at Rockville, PA north of Harrisburg, PA.  It was and is the longest stone arch bridge in the world and remains in use. The approaches to the bridge require a 30 mph speed. The proposed realignment by easing curvature shown in yellow would permit a potential 80 mph passenger speed. This is the last proposed realignment as the Harrisburg passenger station is 4 miles south at milepost 104.9. WHile the proposed alignment shows the existing bridge, a new structure should be built.
Looking east from vicinity of milepost 109.5 the 6 degree curve approach at the east end of the Rockville Bridge shows the need for a 30 mph speed limit.

 Here is the Pennsylvania Railroad's 1925 calendar illustration by artist Harold Brett showing an eastbound passenger train on the east end of the Rockville Bridge
Here is  Conrail freight westbound entering the 6.5 degree curve taking the railroad off the Rockville Bridge south of Marysville, PA. This in the vicinity of milepost 110.7
 This low level oblique aerial photograph shows an eastbound freight train on the Rockville Bridge. The locomotives are at about milepost 110. The foundations for the bridge that preceded the current 1903 Rockville Bridge can be seen diverging from the right side or upstream side of the bridge.

Here the proposed 80 mph realignment for the Rockville Bridge is shown in yellow. The original Pennsylvania Railroad alignment is shown in blue.  Looking west, Marysville, PA is to the right outside of the photograph.
Here a locomotive is seen eastbound in the vicinity  of milepost 109.5. This telephoto was made from the west bank of the Susquehanna River looking at the south side or downstream side of the Roackville Bridge. There is a reason for the bridge color below the center locomotive being beige rather than darker brown. In 1997 the stone wall failed causing a passing train to derail and deposit a number of coal hoppers into the Susquehanna River. The lighter beige color is due to the concrete used to repair the bridge. The concrete was poured into forms that duplicate the look of stone.
This is a detail of the stone construction of the Rockville Bridge. In 1997 a section of the south stone wall failed. The failure caused a derailment on the eastern end of the bridge with some half dozen freight cars falling into the Susquehanna River. There were no injuries.

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