Northeastern Extension's Fifth Decade
By Lowman S. Henry

The 1950's were a decade of unparalleled growth for the Pennsylvania Turnpike and the last of the "boomer-era" expansion projects, the Northeastern Extension, turned 40-years old on November 7, 1997.

When the original Pennsylvania Turnpike opened for business on October 1, 1940, it was just 160 miles long stretching from Carlisle to Irwin. By the late 1940's, the "superhighway" concept had caught America's fancy and travelers longed for a Turnpike which crossed Pennsylvania from border to border.

Harry Truman was in the White House when the Carlisle to Valley Forge extension opened on November 20, 1950 to usher in the expansion decade. Extensions from Irwin to the Ohio Line and from Valley Forge to New Jersey soon followed. But the Northeastern Extension, from Montgomery County in the south to Scranton in the north, was the longest of the expansion projects crossing some 110 miles at a then-hefty cost of $233 million.

In his book on Turnpike history, author Dan Cupper explains that the concept of a branch route of the Turnpike to Scranton had been authorized by the Pennsylvania Turnpike Commission as early as 1947. It was 1954 before financing for the Northeastern Extension was obtained as part of a package deal to also construct the Delaware River Bridge, the final link to New Jersey.

Groundbreaking for the Northeastern Extension was held on March 25, 1954. It would be the last such groundbreaking for an expansion project until August 20, 1989 when the first spades of earth were turned on Turnpike 60, the James E. Ross Highway in Beaver County, launching the 1990's as the next decade of expansion.

Actually, sections of the Northeastern Extension began opening to travelers on November 23, 1955 when a 37-mile segment from Norristown to the Lehigh Valley opened for business. According to Cupper, temporary interchanges at Lansdale and Quakertown opened later that year and another 10 miles of roadway was opened north of Allentown on December 28, 1955.

The new Northeastern Extension had something in common with its parent highway, a tunnel built through the Blue Mountains. To distinguish the tunnel north of the Lehigh Valley from the Blue Mountain Tunnel West of Carlisle, the new tunnel was named the Lehigh Tunnel. Originally, the Lehigh Tunnel was one tube which accommodated just two lanes of traffic.

A 47-mile section of the Northeastern Extension opened on April 1, 1957, including the Lehigh Tunnel and a new 1,487-foot-long bridge over the Lehigh River. But the final 16 miles, taking the Pennsylvania Turnpike to the outskirts of Scranton, opened on November 7, 1957, bringing the Turnpike's total length to 470 miles.

The Northeastern Extension has seen many upgrades during its 40-year history, the most significant being the addition of a second Lehigh Tunnel on November 22, 1991. The new tube was built at a cost of $45 million using a New Austrian Tunnel Method (NATM) in its construction. Previous tunnels built along the Pennsylvania Turnpike involved the blasting through rock which was then stabilized by a steel superstructure. The NATM method utilized a fast-hardening concrete mixture called "shotcrete" which was sprayed on the rocks making a steel superstructure unnecessary.

Interestingly, the Northeastern Extension was the last expansion highway built by the Pennsylvania Turnpike Commission until the 1990's because the new federal interstate highway system met the demand for superhighway construction during the 1960's and 1970's. The Northeastern Extension itself received designation as an interstate highway in November of 1996 when it shed its designation as PA Route 9 and became known as Interstate 476.

More improvements are on the drawing boards for the Northeastern Extension as construction is about to begin on a new Lehigh Valley Interchange in the Allentown-Bethlehem area and renovations will be undertaken at the Hickory Run Service Plaza. This will ensure the continued growth and vitality of a major part of the Pennsylvania Turnpike system.

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