Eastern Railroad Discussion > PRR Shock Mill Bridge collapse and question of RailPace text.

The recent February 2026 Railpace Magazine has a two page story on photographing the Shocks Mill former PRR bridge over the Susquehanna River south of Harrisburg, PA Four of the 6 photographs show the June 1972 collapsed of nine stone piers that were rebuild with steel the following year. The bridge was built on a bed rock river bottom but test drilling showed that the rocks were in separate layer with clay and gravel and while Hurricane Agnes flooded the river for about 14 days, the currents were able to undercut that bed rock.

 I was a Train Master working the terminal at that time and was told the brakeman in the cabin was thrown to the back wall of the cabin account the cabin car dropped and was yanked back up by the coupler as the stone work fell apart directly under it. I never heard what is in the text of this story that the engineer saw the sinking of the rails and stopped his train before going over the center of the river. That meant that every train for a year that used that line had to be routed over the Rockville Bridge, double the traffic.

To prevent gridlock the Superintendent directed a non-agreement supervisor to join the tower operator in every interlocking and report directly to him on any delays and record what the tower operator said and did if something went wrong. I was first assigned to Rockwood tower and later sat in Lemo tower for months. They built a very tight curve to go east from the Cumberland Valley bridge that handled some trains instead of all over Rockville. Those trains were towed out of Enola Yard backward down the CV so they could cross the river eastbound and run to Columbia on the Royalton line.

 Can anyone confirm if the text in the story is right or what the tower operators told me what actually happened at the time?  In July, I walked into the east end of the collaped piers and took photos just like ont nones published in this very nice story.

I was working for Penn Central in Philly when the Shocks Bridge collapsed.  I'm pretty sure that no train or part of a train actually passed over the bridge as it was failing.  On the morning of June 27, 1972 a PC eastbound, PF-6 enroute to Philly, was about to start across the bridge on the sharp curve at the west end when the crew spotted something ahead that didn't look right and stopped the train.  The bridge had begun settling at the point of collapse.  I don't recall what the speed limit was on the bridge back then, but the curve at the west end it is pretty tight so definitely restricted speed and the crew had no trouble getting the train stopped.  Attached is a picture of a Conrail eastbound taken at that curve in November 1976.  According to the report I have, the engine crew of PF-6 then walked across the bridge to the nearest phone box on the east end and called the operator at "Cola" tower in Columbia, Pa., who relayed the info to division HQ in Harrisburg.  The bridge was then immediately closed.  The gradual failure continued until before daybreak on July 2 when six of the 28 spans of the bridge, the ones almost directly in the middle of the river, totally failed and fell into the river.  I don't know what the total cost to PC was to rebuild the bridge while rerouting trains all over the place, but it was money we didn't have.  

Bob

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On second thought, it's entirely possible that the cabin car crew of a previous train might very well have crossed the bridge as it was just beginning to settle and gotten shaken up, especially if that happened before daybreak when it was much harder to spot any irregularity.  Back then probably 30-40 trains a day crossed that bridge.  Only a block or dispatcher's sheet for that day would reveal what other trains might have been in the area.  I don't get Railpace any more so don't have access to the article unless it's online somewhere.

Bob

bobdavis Wrote:
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> I was working for Penn Central in Philly when the
> Shocks Bridge collapsed.  I'm pretty sure that no
> train or part of a train actually passed over the
> bridge as it was failing.  On the morning of June
> 27, 1972 a PC eastbound, PF-6 enroute to Philly,
> was about to start across the bridge on the sharp
> curve at the west end when the crew spotted
> something ahead that didn't look right and stopped
> the train.  The bridge had begun settling at the
> point of collapse.  I don't recall what the speed
> limit was on the bridge back then, but the curve
> at the west end it is pretty tight so definitely
> restricted speed and the crew had no trouble
> getting the train stopped.  Attached is a picture
> of a Conrail eastbound taken at that curve in
> November 1976.  According to the report I have,
> the engine crew of PF-6 then walked across the
> bridge to the nearest phone box on the east end
> and called the operator at "Cola" tower in
> Columbia, Pa., who relayed the info to division HQ
> in Harrisburg.  The bridge was then immediately
> closed.  The gradual failure continued until
> before daybreak on July 2 when six of the 28 spans
> of the bridge, the ones almost directly in the
> middle of the river, totally failed and fell into
> the river.  I don't know what the total cost to
> PC was to rebuild the bridge while rerouting
> trains all over the place, but it was money we
> didn't have.  
>
> Bob
It seems your account largely agrees with this published in the PC POST, this was previously posted on here and the OP pronounced it as "false info", so how about that...

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When was Shocks rebuilt and re-opened? 

One day when I was doing my field work as an inspector I was approached by a trainman who complained about a bridge walkway hazard. Looked at the walkway it had developed a three inch height difference between two walkway plates. Because of the spacing of the bridge ties I couldn’t see the structure under the track. A RR track inspector arrived and took the bridge out of service. Seems the bolts that held a stringer to a cross beam had fallen out. I should mention that this happened about 30 years ago, the bridge spanned the NEC.

Posted from iPhone

> > Bob
> It seems your account largely agrees with this
> published in the PC POST, 

That's exactly where my info came from.  I'm sure I still have that issue around here somewhere.

Bob

The photo obviously has nothing to do with the Shocks collapse.  What/where/when was that wreck?

I agree the article in RailPace is correct as it follows the PC Post account.  Good to know the rumor at that time about the luckest trainman on the PC RR was void of true facts.

PRR1361 Wrote:
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> The photo obviously has nothing to do with the
> Shocks collapse.  What/where/when was that wreck?

Probably one of the many washouts related to the storm.

PRR1361 Wrote:
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> The photo obviously has nothing to do with the
> Shocks collapse.  What/where/when was that wreck?
If you look at the cover, at top right it says "Special issue, The Flood" Notice the date, Aug-Sept. 1972, so this PC Post magazine is obviously all about Hurricane Agnes in 6/1972.
The cover pic is indeed not of Shock's Mill Bridge, but another flood-caused wreck on PC that drew nationwide news coverage, I'm surprised you don't remember it...

PRR1361 Wrote:
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> The photo obviously has nothing to do with the
> Shocks collapse.  What/where/when was that wreck?
On the Wilkes Barre Branch between Northumberland and Wilkes Barre, at the time of the flood.

amtrakbill Wrote:
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> When was Shocks rebuilt and re-opened? 

To answer your question... rebuilding this bridge came with a price tag that started out at $4,500,000 and went to $7.5 million. After being closed for thirteen months Shocks reopened on August 3, 1973.
 

One good thing that came out of the whole fiasco was that a smart division supe got a south leg added to the northward curve from the bridge leadiing into the passenger station, creating a full "wye".  That eliminated a long and circuitous backing move to get to/from Enola.