In the aftermath of the tragic May 12 derailment due to excessive speed of Amtrak train 188 in Philadelphia, many casual observers wondered what a 50-mph curve is doing in the middle of the fastest, busiest rail corridor in the nation. It’s a reasonable question, especially given the generally tangent track and flat topography in the area.
The existence of that curve traces back to the earliest years of railroads in Philadelphia. As in many cities, Philadelphia's rail network developed in piecemeal, uncoordinated fashion. What became Amtrak 188’s route through the city began in the 1830s as three separate projects.
The sharp curve at Frankford Junction, where Amtrak 188 derailed, dates from 1867, when the Connecting Railway was joined with the Philadelphia & Trenton.
The Philadelphia, Wilmington & Baltimore ran generally southwestward from a terminal about a mile south of downtown (“center city” to Philadelphians). The Philadelphia & Columbia, part of the Main Line of Public Works rail/canal system to Pittsburgh, utilized a terminal in center city. The Philadelphia & Trenton, which connected with services to New York, originated in Kensington — an inconvenient 2½ miles northeast of center city. As Albert Churella relates in the first volume of his mammoth history of the PRR (University of Pennsylvania Press, 2013), municipal authorities in 1840 granted the P&T permission to extend its line into center city, where it would connect with other railroads. However, fierce opposition from teamsters, who profited from hauling freight between the rail terminals, and area residents, who did not want steam trains in their streets, prompted the city to revoke permission, and the P&T was not extended.
Two decades later, it was clear that the three lines should be connected. In 1864 the Junction Railroad was opened, linking the PW&B with the P&C’s successor on the line to the west — the Pennsylvania Railroad. (Indeed, the PRR had interests in all three of the lines by this time.) Three years later the Connecting Railway opened. It diverged from the P&C/PRR line at a place designated Mantua Junction (and later, in expanded form, Zoo interlocking), arced around the northern part of the city, and connected with the P&T in the Frankford section of Philadelphia. As with the connection at Mantua Junction, the geometry of the lines at Frankford Junction resulted in a sharp curve.
By the 1890s, all these lines were part of the PRR’s busy Washington–New York main line. In 1896, the PRR built a line southeast from Frankford Junction — more or less as a straight extension of the old Connecting Railway — to the new Delair Bridge across the Delaware River into New Jersey. The Delair Bridge line became a major passenger and freight route, while the portion of the old P&T southwest of the junction served as a local freight feeder. Thus for more than a century Frankford Junction’s primary importance has been as the point where the Delair line split from the main line. Today, the Delair line remains busy with NJ Transit, Norfolk Southern, and CSX trains leaving and entering the Northeast Corridor, while the P&T line to Kensington has withered in the manner of many urban industrial branch lines.
Even before May 12, Frankford Junction had a place in passenger train infamy. On September 6, 1943, a journal burned off one of the cars in the New York–bound Congressional Limited just as the train passed Shore Tower, which controlled the western portion of the junction. In the resulting derailment, two cars were smashed against a signal bridge, and 79 people were killed, making it one of the worst train wrecks in American history. However, the 50-mph curve was not a factor in the tragedy.
Nevertheless, that curve had long been recognized as a kink in an otherwise mostly straight, fast route. In fact, the PRR once seriously considered realigning it to permit higher speeds. David Messer in his book Triumph III (Barnard, Roberts, 2000), reveals that in 1902 the railroad got as far as acquiring land on the north side of the Frankford Junction curve in preparation for easing it significantly, and even did some grading. This was at the peak of PRR’s epic — and expensive — program of line improvements and extensions, and the road apparently decided its resources could be better used elsewhere. The Frankford Junction realignment was shelved.
Had the Philadelphia & Trenton been able to extend its line to center city in 1840, Philadelphia’s rail network might have developed differently. Perhaps the Connecting Railway — and the Frankford Junction curve — would not have been built. Had the Pennsylvania followed through with the 1902 realignment, the 4-degree curve would have been eased, and Amtrak 188 — even traveling 106 mph, as it was on May 12 — might have negotiated it without derailing, and 8 of its passengers would be alive today.