Urban Planning

Carstairs Row

Perhaps one of the things Philadelphia is famous for is its abundance of rowhouses. In fact, rowhomes are the single most numerous type of housing in the city. From small, utilitarian houses in the older sections of Philadelphia such as Queen Village to the large rows complete with porches, bay windows, and gingerbread trim in West Philadelphia, the row home provided Philadelphians with a space efficient and cost efficient means of housing in a rapidly expanding and industrializing city.

In envisioning Philadelphia, William Penn had planned a “greene country towne” where homes would occupy big open lots. However, Penn’s first purchasers quickly divided and sold parts of their plots to new arrivals who wanted to live close to the business and industrial areas by the Delaware River. The area towards the Schuylkill River remained undeveloped however. At a time when most people got around by foot, living even this short distance from the main areas of activity was akin to living virtually disconnected from the city. As plots near the Delaware River were divided and further subdivided, Penn’s green country town quickly began to resemble the crowded cities of Europe that he had hoped Philadelphia would stand in stark contrast to. Houses and shops were erected right next to each other, often sharing a wall on one or both sides. Indeed, this type of “terraced housing” was the most common type of housing in European cities.

Philadelphia’s Elfreth’s Alley is hailed as the longest continually occupied street in the country. It would therefore be easy to assume that the attached houses on Elfreth’s Alley are the oldest rowhouses in Philadelphia. However, on closer inspection, the different facades and rooflines of the Elfreth homes show us that they were built at various times and by different builders. This can also be applied to other colonial-era housing in Philadelphia. The homes may share walls, but this was done more so out of necessity rather than planning.

The first planned row of look-alike housing to be built at one time was Carstairs Row at South 7th and Sansom Streets. Begun circa 1799, Carstairs Row was the brainchild of developer William Sansom. Sansom purchased the property at Walnut Street between Seventh and Eighth Streets at a sheriff’s sale. The land had previously belonged to Robert Morris, and the sale included Morris’ unfinished mansion designed by L’Enfant (and sometimes referred to as Morris’ Folly). Since this area was still undeveloped and a bit off the beaten track at the time, Sansom’s purchase and development of the land was the first speculative housing development in the United States. Sansom then bisected the property with his namesake street. In order to attract potential tenants, Sansom used his own money to pave the Sansom Street at a time when most other Philadelphia streets were little more than dirt roads. Sansom then hired architect Thomas Carstairs to design a row of twenty-two look-alike houses on the south side of Sansom Street. The rowhouses were the first to be purposely designed to have uniform facades and share walls.

Today, Carstairs Row is a part of Philadelphia’s famous Jeweler’s Row. The continuous flat facades of Carstairs Row meant easy conversion into commercial properties. Though Carstairs Row still exists, it has been heavily modified and updated over the centuries to fit changing business needs and requirements. Numbers 730 and 732 Sansom Street have retained some elements of their original design but raised entrances and other changes fundamentally alter their facades. However, 700 Sansom Street, one of the corner properties, remains remarkably unchanged since it was originally built. It stands as yet another example of the Philadelphia of the present coexisting with elements of the rich history of Philadelphia’s past.


Ames, Kenneth. “Robert Mills and the Philadelphia Row House,” Journal of the Society of Architectural Historians, Vol. 27, No. 2 (May, 1968): 140.

Philadelphia Architects and Buildings,

Schade, Rachel Simmons. “Philadelphia Rowhouse Manual: A Practical Guide for Homeowners,” Philadelphia City Planning Commission and The National Trust for Historic Preservation,

Wolf, Edwin. Philadelphia: Portrait of an American City. (Philadelphia, Pennsylvania: Camino Books/The Library Company of Philadelphia, 1990), 129.

Urban Planning

The Pennsylvania Railroads Philadelphia Improvements, Part II

Last month we looked at the Pennsylvania Railroads Philadelphia Improvements starting with the construction of Suburban Station followed by construction of the north wing of 30th Street Station, which opened September 28, 1930. Despite the Depression, construction would continue on the remaining major portion of 30th Street Station. From the outset, the Pennsylvania Railroad intended the station to be a magnificent structure. After soliciting numerous design proposals, the railroad finally settled on the architectural firm of Graham, Anderson, Probst and White for their design of a Grecian style station built of structural steel and concrete faced with Alabama limestone.1

Two aerial photographs and show the early stages of construction. It should be noted that the date of 1934 for these photographs is incorrect since the station was already in partial service by 1933.2 By comparing numerous aerial photographs documenting the progress of the station’s construction, a more accurate date for the first photograph is February of 1931 and the second photograph would be late spring of 1931. The first aerial photograph shows the completed suburban wing of the station. Adjacent to the suburban wing (directly below it in the photograph) one can see that the tracks formerly used to enter Broad Street Station via the three railroad bridges have been removed. The second aerial photograph, taken a few months later, shows the area adjacent to the suburban wing as a white rectangular area. This represents the construction of the street level floor of the station.

Tracks entering the station are below this level. In order to accommodate the tracks a large amount of earth was first excavated from this area. This was not without incident, as it was discovered that the area was used as a burial site for 17th century Quakers and a number of coffins were unearthed and had to be relocated. After the earth had been excavated, securing the foundation required that 5000 pipes be driven into the ground some 80 feet deep to encounter bedrock. Once the pipes were filled with concrete, assembly of the structural steel could begin.3 Concomitant with work on the building, much of the site to the north and south of the building needed to be cleared for railroad tracks. In the aerial photographs, the buildings just north of the newly completed suburban wing were stockyards and an abattoir that had been razed for construction.

By the end of 1931, the structural steel framework of the building was near completion and the outer limestone walls were being erected. When completed the station was indeed magnificent. At each end of the concourse on the outside were porticoes, one facing 30th street the other the Schuylkill River and downtown Philadelphia. Each portico has ten Corinthian columns measuring 71 feet tall and 11 feet in diameter.4 Inside the station, the main concourse is 290 feet long and 135 feet wide. The ceiling towers some 95 feet above the Tennessee marble floor. Much of the ornamentation within the station represents a beautiful example of art deco design.5 Work continued on the station for the next two years, and the station was fully opened on December 15, 1933. The station remains active today and is Amtrak’s third busiest railroad station behind only Penn Station in New York and Union Station in Washington D.C.

While the station remains intact, a number of dramatic changes have occurred in the last few years. The most significant is the construction of the Cira Building just north of the suburban wing. A final note concerns the steam generation plant for 30th Street Station with its very tall smokestack visible in the aerial photographs and on the extreme left in the photograph of the portico. Built in 1929, it has apparently become expendable and is scheduled for implosion in November 2009, thus removing a familiar landmark from the West Philadelphia skyline.


[1] Underkofler, Allen P. The Philadelphia Improvements Part II: 30th Street Station. The High Line, Vol. 3, Nos. 1 & 2 (Sep. 1980), p. 6

[2] Ibid., p. 11

[3] Ibid., p. 11

[4] Ibid., p. 7

[5] Ibid., p. 6

Urban Planning

The Pennsylvania Railroads Philadelphia Improvements, Part I

During the early 1920s, the Pennsylvania Railroad began planning for major changes to its infrastructure in the busy Philadelphia area, with the goal of expediting passenger traffic. While Broad Street Station presented an ideal location for the termination of inbound commuter traffic, a major drawback was its stub-ended design, which forced through trains destined for other cities to retrace their steps to West Philadelphia Station before continuing their journey.
To resolve this problem, the railroad planned two large construction projects.1 The first part of the plan was to replace the company headquarters housed in Broad Street Station with a new building adjacent to the station, along what is now JFK Boulevard between 19th and 20th Streets. Beneath this building, a station would be constructed that would serve as the terminus for electric commuter cars coming in from the outlying areas of Philadelphia. This new station would be known as Broad Street Suburban Station or just “Suburban Station”.

Not wishing to retain the street-obstructing elevated trackage leading into Broad Street, often referred to as the “Chinese Wall”, the planner chose to have the tracks from West Philadelphia quickly descend below street level after they had crossed to the east bank of the Schuylkill River. In order to dig this subway, buildings between Filbert and Cuthbert Streets from 15th Street west to the Schuylkill River were demolished. The second part of the plan was to replace West Philadelphia Station with a large passenger station on the grand scale, similar to Penn Station or Grand Central Station in New York City.2 The plans were approved by the Pennsylvania Railroad’s Board of Directors and agreed upon by the City in 1925. Major construction, however, did not begin until 1927.

The Suburban Station office building was completed in 1929. It represents an absolutely beautiful example of Art Deco design. The first two floors are polished black granite, while the remaining 20 floors are made of Alabama limestone and sandstone.3 Adorning the first floor is bronze work, complete with the familiar Pennsylvania Railroad keystone logo. The station below the building was opened on September 28, 1930. Commuter trains leaving Suburban Station crossed the Schuylkill River on a newly constructed stone arch bridge that would eventually serve as the replacement for the three separate railroad bridges that carried trains into Broad Street Station.4

Interestingly, the only portion of 30th Street Station that was constructed at the time Suburban Station was opened was the north wing, intended for commuter trains. Construction of the main portion of the station had only just been started, partly because of protracted negotiations with the city and the Philadelphia Rapid Transit Company (PRT) regarding the Market Street Elevated Line that would run along the south side of the station.5 As originally planned, the elevated would have passed through a south wing of 30th Street, symmetrical with the suburban north wing of the station. However, the Pennsylvania Railroad felt that the bridges of the elevated line would detract from the appearance of the station and negotiated with the City and PRT to place the elevated line in a subway instead. Unfortunately, as this 1949 picture shows, it took many years for the City to do this and the railroad was left with the rather unsightly elevated line running by its magnificent station.

Next month, we will look at the construction of 30th Street Station. In retrospect, looking at the scale of these projects and the fact that the nation was now at the height of its worst economic depression, it is a tribute to the Pennsylvania Railroad that it was able to complete them under such dire circumstances.


[1] Underkofler, Allen P. The Philadelphia Improvements Part I: The Idea & Projects East of the Schuylkill River. The High Line, Vol. 2, Nos. 2 & 3 (May 1979).

[2] Underkofler, Allen P. The Philadelphia Improvements Part II: 30th Street Station. The High Line, Vol. 3, Nos. 1 & 2 (Sep. 1980).

[3] Messer, David W. Triumph III: Philadelphia Terminal 1838-2000. Baltimore, MD: Barnard, Roberts & Co., 2000, p 52.

[4] Ibid., p. 64.

[5] Ibid., p. 65.

Urban Planning

The Reading Railroad’s Turn of the Century Big Dig, Part Two

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Last month, we discussed the Reading Railroad’s ambitious plans for placing their City Branch below ground level. One part was the construction of a tunnel beneath Pennsylvania Avenue. The tunnel was to be 2888 feet long and of sufficient width to hold four tracks, two for the main line into the city and two for storage.1 At the time, steam power still ruled the rails, so providing suitable ventilation for a tunnel of this length was not a trivial engineering problem. Extensive correspondence over the issue survives in the Reading archives. Ultimately, the problem was solved by placing a series of ventilating grates down the median of Pennsylvania Avenue above, much like Park Avenue in New York City.

A recent featured photograph shows the setting of the keystone at the east portal of the tunnel in 1898 and the completed tunnel in 1900. Construction of the tunnel was not done by boring underground but rather by using the “cut and fill” technique in which the earth is first excavated and retaining walls and roof constructed, after which earth is backfilled on the roof.

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Beyond the tunnel, the remainder of the line was an open subway of almost equal length stretching from 20th Street down to 13th Street. At the turn of the century, this was still one of the key manufacturing areas of Philadelphia, and the industries there depended on railroad access. Alongside the tracks that constituted the mainline, the Reading constructed additional sidings and storage yards that served these industries. The unquestionably dominant industry along the City Branch was the Baldwin Locomotive Works, which by 1905 was the largest employer in the region with a workforce of over 15,500 individuals.2 Adjacent to Baldwin Locomotive Works was the plant of William Sellers & Co. at 16th Street. While not as large as Baldwin, the company’s owner designed and successfully campaigned for the use of the first U.S. standard screw thread, which had a major impact on standardization in manufacturing practices.3 The complex trackage in the area allowed Reading switchers to shove freight cars from their subway up an incline to street level and then cross back over the subway tracks on an angled girder bridge into the factory.

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Along with the tracks leading into the Baldwin plant between 15th Street and Broad Street, the railroad also built a substantial freight yard on either side of Broad Street. In later years, the air space over these yards would be utilized by constructing buildings over the tracks. The Inquirer Building (actually the Elverson Building, named after the owners) was constructed in 1925 between 15th Street and Broad Street and supplied the Reading Railroad with another customer requiring shipments of newsprint.4

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On the east side of Broad Street, the Reading would, in 1930, construct its own multistory warehouse over the tracks, replacing the rather modest one-story freight sheds which had previously occupied the site. The Terminal Commerce Building, as it was called, still stands today and is a beautiful example of Art Deco architecture. While the tracks and many of the industrial buildings are gone today, the pictures remind us of Philadelphia’s rich industrial history that earned it the name of “Workshop of the World”.

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[1] Engineering department notes, Reading Company Collection, Hagley Museum and Library.

[2] Scranton, P. & Licht, W. Work Sights. Temple University Press, Philadelphia (1986), p. 182.

[3] #234 The United States Standard Screw Threads (1864) American Society of Mechanical Engineers. Accessed May 25, 2009.

[4] Workshop of the World. Oliver Evans Press, Philadelphia (1990), pp. 5-43–5-44.

Urban Planning

The Reading Railroad’s Turn of the Century Big Dig, Part I

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If one were to explore the neighborhood just north of Callowhill Street between 20th and Broad Street, the casual observer might be perplexed by what appears to be a sunken urban greenway running parallel to Callowhill Street. This trench, some 40 feet wide and 20 feet deep, is now overgrown with trees and littered with trash. While it is hard to imagine, this was once a busy railroad thoroughfare belonging to the Philadelphia & Reading Railroad. The origins of this portion of the railroad date back more than a century and represented an important route for the Reading to deliver goods into Center City. In the mid 1800’s, the Reading, whose main terminal was at Port Richmond, was looking for access to the heart of Philadelphia. Its chance came in 1850, when it bought the old Philadelphia and Columbia line between Peter’s Island in the Schuylkill (Belmont) and Broad and Vine Streets.1

By 1893 the volume of railroad traffic along this line, which the Reading referred to as its City Branch,1 had become so great that the city fathers felt it necessary to intervene.2 At this time, all the railroad trackage was at street level, which meant numerous grade crossings as the railroad traversed the grid of Philadelphia streets. A nice example is at Broad and Noble Streets, where at least three tracks crossed the intersection, complete with crossing gates and watchman’s shanty. In addition to the traffic problems this arrangement created, the city fathers were sensitive to the fact that as the railroad traveled south along the east bank of the Schuylkill River, it ran right in front of the entrance to Fairmount Park, a less than pleasing spectacle. As part of an agreement to allow the Reading to build its new passenger terminal at 12th and Market Street, the railroad was also required to find some solution to the problem of street trackage.2

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After numerous plans it was finally decided that the tracks would be placed below street level, an interesting departure from the usual railroad strategy. Both the Reading Railroad and its rival, the Pennsylvania Railroad, typically opted for grade elevation rather than lowering the track, a prime example being the Pennsylvania Railroad’s elevated trackage into Broad Street Station, later nicknamed the “Chinese Wall”. The project would consist of two major parts. The first was along Pennsylvania Avenue from Taney Street east to 21st and Hamilton. Four tracks would be placed in a tunnel running underneath Pennsylvania Avenue. The second part was an open subway from 21st Street to 13th and Callowhill.2

Work began in 1897 and the magnitude of it cannot be overstated. There was an enormous amount of earth to be excavated. In addition, there was the logistical nightmare of doing construction without disrupting service to various industries along the line, so temporary track needed to be laid. Since the track was going below street level, various sewer lines had to be rerouted, and bridges needed to be constructed to keep through streets open. Even the railroad’s own engine servicing facilities would be demolished so that the tracks could be lowered.

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Despite the immense scope of the project, much of the work was completed within two to three years. By 1900 the line was fully functional and connected to the Reading Passenger Terminal at its eastern terminus. The line remained active for nearly 100 years. In 1984, the Reading Terminal closed, and by 1997, the last remaining freight customer along the line closed, marking the end of rail service.3 While little remains today of what was once a key industrial section of Philadelphia, we will look in Part II at a number of places along the line during construction and see the importance of the railroad and the industries it served.


[1] Pennsylvania Railroad Company. “Inspection of Physical Property by Board of Directors, November 10-11-12, 1948.”

[2] Webster, George S. and Wagner, Samuel T. “History of the Pensylvania Avenue Subway, Philadelphia, and Sewer Construction Connected Therewith.” Transactions of the American Society of Civil Engineers, v. XLIV (Dec. 1900), pp. 1–33.

[3] Castelli, Douglas, Hill, Erin, Johnson, Michael & Jones, Dayle. “Innovative Rail Technologies Cross-Town Rail Line: Final Report.” Appendix B. (2003)

Historic Sites Urban Planning

Broad Street Station

While intercity travel today primarily involves the automobile or airplane, a century ago the passenger train represented the principal mode of long distance travel. The increasing volume of rail passengers in the late 1800’s required railroads to find efficient ways of delivering passengers to their destinations. In Philadelphia, the problem for the Pennsylvania Railroad was the lack of a station that would deliver passengers directly into Center City Philadelphia. In 1879, the railroad devised a plan to construct a large passenger station at Broad and Market Streets, directly opposite City Hall. The station would be connected by multiple tracks to the Pennsylvania Railroad station located in West Philadelphia, across the Schuylkill River1. The extension would have required numerous street crossings, starting at 23rd St. and going eastward towards Broad Street. To avoid both the safety hazard of street crossings and the potential bottleneck they would create for the numerous passenger trains, it was decided to construct the tracks on an elevated embankment. Large granite blocks were used to enclose the embankment and over time the structure was often referred to as the “Chinese Wall” because of its resemblance to the Great Wall of China2. In later years this structure would become the bane of city planners because it was viewed as an impediment to development of the area north of Market Street3.

Broad Street Station was officially opened on December 5, 18814. The brick station was of Gothic design with a rather ornate Victorian appearance. Behind the station were four train sheds to protect passengers from the elements. The station was an immediate success, boasting 160 daily trains5. The volume of passenger traffic steadily increased, so that by 1886, the number of passengers using the station averaged a million per month6. As a consequence, in 1892, a mere eleven years after its opening, plans were submitted for the enlargement of the station. An office building that would serve as the Pennsylvania Railroad’s headquarters was designed by noted architect Frank Furness and added to the existing station7. The smaller train sheds were replaced by one massive train shed 306 feet wide and 591 feet long. The roof, made of wood and glass, was at its highest point 100 feet above the tracks8.

Already by 1910, the 16 tracks of the station saw 578 arrivals and departures daily9. At the same time, the success of Broad Street Station brought with it a number of problems. While it served well as a final stop for commuter traffic into Center City, it was inconvenient and time consuming for through trains because they were required to retrace their steps to West Philadelphia Station before continuing on their journey. The stub-ended design of Broad Street required arriving locomotives to back up and be turned on a turntable before they could depart, creating additional congestion. A partial solution was provided by the railroad’s electrification, allowing the use of multiple-unit commuter trains which could operate in either direction.

On June 11, 1923, a fire broke out below the station platforms and quickly spread to the train shed, engulfing the entire structure in flames. Within hours of the fire, the Pennsylvania Railroad marshaled a work force of some 3500 men to begin repairing the station. Within five days, all tracks and platforms were restored. The weakened train shed was dismantled and replaced with umbrella shelters10. However, the handwriting was on the wall for Broad Street Station.

Within two years, the Pennsylvania Railroad started drawing up an ambitious plan, referred to as the “Philadelphia Improvements,” that called for the construction of 30th Street Station as the railroad’s main passenger station in Philadelphia, replacing the West Philadelphia station11. The plan also called for the elimination of Broad Street Station, replacing it with an underground station for commuter trains, known as Broad Street Suburban Station (but usually referred to simply as Suburban Station). By 1929, the excavation for the trackwork leading to Suburban Station had begun, parallel to the north side of the Chinese Wall. A year later, the construction of 30th Street Station across the Schuylkill River began, and Broad Street Station’s days were numbered. Surprisingly, the station was used for two more decades before finally closing on April 27, 1952. Aboard the last train from the station rode the Philadelphia Orchestra, led by Eugene Ormandy conducting a rendition of “Auld Lange Syne”12. Within a year, the station was demolished, making way for Penn Plaza and a series of high rise office buildings.

[1] Pennypacker, Bert (December 1983). “The Grandest Railway Terminal in America”. Trains (Kalmbach Publishing Co.): 40-57. ISSN 0041-0934.

[2] Albrecht, Harry P. [1972] (1976). Broad Street Station. Clifton Heights, Pennsylvania: Harry P. Albrecht. p. 3.

[3] Underkofler, Allen P (1987). “The Philadelphia Improvements, Part I”. The High Line (Philadelphia Chapter, Pennsylvania Railroad Technical and Historical Society) 2 (2 & 3). p. 5.

[4] Albrecht, p. 3.

[5] Pennypacker, p. 44.

[6] Ibid., p. 45.

[7] Messer, David W. (2000). Triumph III: Philadelphia Terminal 1838-2000. Baltimore, Maryland: Barnard, Roberts & Co. ISBN 0-934118-25-6

[8] Pennypacker, pp. 46-47.

[9] Ibid., p. 49.

[10] Ibid., pp. 51-52.

[11] Underkofler, pp. 6-15.

[12] Pennypacker, p. 57.

Urban Planning

Creativity in Cast Iron: Strickland Kneass’s Chestnut Street Bridge

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For Strickland Kneass (1821-1884) engineering was not about letting tradition dictate uninspired designs nor did the profession thrive in clannish fiefdoms of expertise. Trained in the era before formal engineering curricula, Kneass saw engineering as an organic profession whose rules, though important, were always secondary to imaginative solutions. In his nearly half century of work in the private sector and his seventeen years of service to the City of Philadelphia as Chief Engineer and Surveyor, as a sewer and drain expert, as a bridge builder, and as Fairmount Park Commissioner, Kneass distinguished himself as a polymath designer and organizer who deftly navigated between the shoals of tradition and innovation.

The remains of Kneass’s boldest design, a bridge whose scale and use of cast iron made it singular in the United States and throughout the world, stands ignored by hundreds of thousands of motorists, pedestrians, and joggers who pass it. A vestige of his Chestnut Street Bridge (1861-66): the eastern granite abutment and the central pier, though ignobly incorporated into the current highway overpass, still testifies to the creativity and vision of one of the city’s most talented builders.

The son of a Philadelphia engraver, Kneass attended the Rensselaer Institute, later Polytechnic Institute, when that institution began developing its own idiosyncratic approach to training civil engineers. For a young Kneass attending the Troy, NY school in the late 1830s, the curriculum—which still included geology, law, Biblical history, and surveying—was far from a dry inculcation of mathematical formulae. Despite a rigorous schedule that roused students at dawn, “there was considerable flexibility, informality, and probably even laxity in the actual operation” of the school. Students were taught to work through problems, develop their own conclusions, and report on their findings during examinations. A Rensselaer engineer, an advertisement touted, “are taught all these things (23 subjects of civil engineering) and many others, with the appropriate instruments in their hand, accompanied by short lectures of their own.”

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Graduating in 1839 at the age of 18 with full honors, Kneass reaped the benefits of this diverse technological education and soon lived up to the reputation of the multifaceted Rensselaer engineer. In 1847 he assisted the Pennsylvania Railroad in laying out a portion of their Harrisburg to Pittsburgh segment. He also worked as a draftsman at the Naval Bureau of Engineering and as a topographer for the British Commission mapping the U.S.-Canadian border. Later, in 1869, he assisted James Worrall in surveying the famous 12 Mile Arc border between Delaware, New Jersey and Pennsylvania.

In 1855, Kneass resigned as chief engineer for the North Pennsylvania Railroad to become Chief Engineer and Surveyor of the City of Philadelphia.  He found the bureaucracy of the recently-consolidated city in shambles. He soon concentrated all the operations of the seven survey districts and standardized grade plans, weights and measures, and designs for sewerage. In 1865 he organized a Registry Bureau as the central repository for property data and building plans. All the while he made recommendations for the improvement of the city’s sewer and storm water systems.

Undoubtedly, Kneass stayed abreast of the new developments in bridge construction; he knew of popular ornamentation then in vogue in Europe and construction management methods. He probably followed the reorganization of his alma mater on the pattern of the progressive French Ecole Polytechnique. He certainly knew of the iron bridge at Colebrookdale, England over the Severn River—the often-reproduced icon of the Industrial Revolution built in 1791. Perhaps closer to home, he knew of William Strickland’s use of iron members at the Chestnut Street Theater. And he may have recalled the work of two innovative Army engineers at Dunlap’s Creek in Brownsville, Pennsylvania. There, Captain Richard Delafield and Lieutenant George W. Cass constructed the country’s first metal arch bridge in 1836 as part of the Cumberland Road.

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The success of these projects, and a willingness to try new materials, may have influenced Kneass’s design for the Chestnut Street Bridge in 1857 which included an unprecedented amount of cast iron. Though it is unclear who supplied the cast iron, two features made iron attractive.  One was the adaptability of the casting process.  Artistically and practically, cast iron offered designers great flexibility.  Bridges made of a multitude of smaller, mass-produced components could be assembled easier and were inherently safer.    This, coupled with the proximity of Philadelphia’s cast iron suppliers, led Kneass to build a bridge around two sweeping 184’ arches using six cast iron ribs. Yet Kneass was no bare functionalist and his line and watercolor drawings abound with Gothic arches in stone and iron. And though Kneass was applying an untested material to a major arterial bridge, he still followed an important standard practice: overbuilding the bridge to ensure safety redundancy. Each rib, he estimated, could sustain a transient load of 486,000 lbs. Anticipating increasing traffic, Kneass wanted wider approaches—a detail the shortsighted city councils wrong-headedly vetoed as the bridge had to be widened in 1911.

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Construction began in 1861 and by 1864 the center pier was completed as evidenced by the date “1864” etched into the stone shield on the central pier’s southern side. Two years later the bridge opened to the public at a cost of $500,000. For most of the latter half of the nineteenth century, the bridge remained a point of pride for American civil engineers. “As far as known, with the exception of the Chestnut-street bridge, Philadelphia,” wrote engineer Malverd Abijah Howe in 1897, “there are no cast-iron arch bridges of any magnitude in the United States.” Despite its apparent stolidity Strickland Kneass’s Chestnut Street Bridge did not last a century and it was demolished in 1958, perhaps because its massive western abutment sat right in the path of the Schuylkill Expressway.

Works Cited:

  • Gilchrist, Agnes.  “Chestnut Street Bridge,” Historic American Engineering Survey, (Washington: National Park Service, 1958), 2.
  • Graff, Frederic.  Obituary Notice of Strickland Kneass, Proceedings of the American Philosophical Society, Vol. 21, No. 115. (Apr., 1884), pp. 451-455.
  • Howe, Malverd A.  A Treatise On Arches: Designed for the Use of Engineers and Students in Technical Schools (New York: John Wiley and Sons, 1897), xvii.
  • Rezneck, Samuel.  An Education for a Technological Society: A Sesquicentennial History of Rensselaer Polytechnic Institute (Troy: RPI, 1968).

Urban Planning

The Olmsted Brothers’ Artificial Nature: South Philadelphia’s League Island (F.D.R) Park

When author Christopher Morley sauntered around “the Neck” one hot summer evening in the early 20th century, to his surprise he found Philadelphians living an almost rural existence amid the marshes, ash heaps and junk yards. But Morley saw that the boggy land where the Delaware met the Schuylkill – “the canal country of South Philadelphia” – held great promise. He longed to see the “wonderful Dutch meadows of the Neck reclaimed into one of the world’s loveliest riverside parks.”

Perhaps Morley knew of the city’s plan for a South Philadelphia park -perhaps he did not- but as early as 1899 the New York Times was announcing with subtle hauteur that “the winning plan for the new League Island Park at Philadelphia was drawn by a New Yorker, Samuel Parsons Jr.” But to the Times, the conditions of the site looked bleak: “the territory where it is proposed to lay out this park consists of 300 acres of low-lying land on the Delaware River…. Irrigation ditches, a sluggish, winding stream, and a small amount of what may be termed upland are all that at present represent the park.”


Though city planners placed Parsons’s design on its 1904 Plan of Park and Parkway Improvements in South Philadelphia and began laying out his design, by 1910 work had ground to a halt. Then in 1912, the city’s director of public works, Morris Cooke, asked the preeminent landscape architecture firm, Olmsted Brothers, to produce designs for League Island Park, Oregon (Marconi) Plaza and the stretch of Broad Street connecting the two parks known as the Southern Boulevard. The Olmsted firm, helmed by the son and stepson of noted landscape architecture pioneer Frederick Law Olmsted, produced two plans that worked with the low lying tidal conditions of League Island’s site. An earlier Olmsted plan borrowed Parson’s design feature of a large plaza in the center of the park along Broad Street. Later plans omitted this formal plaza. But all three designs were not short on water.

The final Olmsted plan situated Meadow Lake and Edgewood Lake inside a ring of carefully segregated lawns, meadows, and “playsteads”. While the area east of Broad Street was designed for active recreation, the western portion was to be a “landscape park.” Incorporating the design features developed by their father, the Olmsted Brothers ran curvilinear paths throughout the complex of open space and water. Just like their father’s Central and Prospect Parks in New York, a combination of altered topography and tree screens effectively walled off the city. The Olmsteds also sought to remake portions of Parson’s design: they adjusted the drives, simplified the drainage system, and made features of the park more “natural”. Thus, lawns and marsh plantings near the lakes replaced severe concrete retaining walls. (Note: some of the photos included in this essay show the retaining wall prior to demolition.) The whole effect was to create a series of well-structured, picturesque natural views and to segregate recreation spaces according to their function.


Beneath the surface, a sophisticated drainage system connected the lakes to the alluvial waters of the Delaware and Schuylkill rivers. This connection allowed them to “breathe” or expand and contract depending on the tides. Portions of Hollander Creek, the “sluggish, winding stream,” was banished to a viaduct and connected to the rivers.

Although the Olmsteds considered their design inalterable, League Island Park underwent substantial modifications almost as soon as it was completed in 1921. New structures were added for the Sesqui-Centennial of 1926 and the original boathouse on Edgewood Lake was converted into a Russian Tea House. The John Morton Memorial Building, now known as the American Swedish Historical Museum was added north of Edgewood Lake in 1926. Other portions of the Olmsted design have been irrevocably obliterated. The decision to construct a municipal stadium on the recreation space land to the east of Broad Street ensured that this part of the park would forever be a stadium complex. A golf course, added in 1940 in response to changing recreational tastes, removed the western portion of the Park. By the late 1940s, even the Park’s name had changed to honor America’s Depression-era and wartime leader. And although the encroachment of I-95 appears the most grievous assault on the park; its looming presence has given an unmistakable ambiance to Philadelphia’s world-class FDR skate park.


While recreational tastes may change, officials at the Fairmount Park Commission have seen the practical wisdom and natural simplicity of the Olmsteds’ plan. When tidal waters began to seep up through the bottom of FDR’s large concrete pool made from Meadow Lake, park landscape architects converted the pool into a natural marshland.


  • Morley, Christopher. Travels in Philadelphia, (Philadelphia: David McKay Company, 1920), 65.
  • Heilprin, Angelo. Town Geology: The Lesson of the Philadelphia Rocks, (Philadelphia: Academy of Natural Sciences, 1885), 125.
  • “Proposed League Island Park at Philadelphia,” The New York Times, 2 April 1899.
  • “League Island Park (F.D.R. Park) Historic District Building Inventory” (Philadelphia: Philadelphia Historical Commission, 2001), 1-6.
  • Fairmount Park Commission Archives.

Urban Planning

The Schuylkill Expressway: Modern Highway or "Worst Mistake"?

Though he later regretted his steadfast support for the intrusive road, mayor Richardson Dilworth saw the construction of the Schuylkill Expressway as a necessary component of the region’s postwar transportation overhaul. To Dilworth and other transit planners, the specter of gridlocked colonial streets loomed large. As early as 1931, a regional planner had derided Philadelphia’s lack of interest in the public infrastructure, calling the city a “growing child in late adolescence,” or “an ailing adult . . . rotting at the core.” With the Depression and World War II intervening, Philadelphia’s situation was dire. In 1955, the Urban Transportation and Traffic Board, an organ created by mayor Joseph Clark to better coordinate transit infrastructure, advised the creation of an 11-county transportation authority with wide control over mass transit, parking, traffic control, buses, and transportation in the air and on water. And pro-growth citizen groups like the Greater Philadelphia Movement and the Philadelphia Citizens’ Council on City Planning joined the official planners in support of a regional network of modern multi-lane limited access freeways. For the businessmen who comprised these organizations, an integrated transit and highway system would assure that center city would remain the healthy cultural and commercial core of the region. Richardson Dilworth understood what was at stake. In an editorial in the New York Herald Tribune, Dilworth portrayed the economic health of a central business district as a general barometer of regional health. “This center city,” he wrote in 1958, “must serve as an effective capital to its area by providing the headquarters for industry, business, banking, hotels, merchandising, medicine, entertainment and culture.”

As early as the 1930s, planners had dreamed of a woodsy, genteel parkway through the Schuylkill River Valley that would connect the then-state park at Valley Forge with Philadelphia’s Fairmount Park. The parkway, limited only to automobiles, would offer an aesthetically-controlled and measured movement through the natural landscape. Yet this vision of a sedate, visually appealing drive fell to the exigencies of regional planning and traffic engineering. By 1947-48, the design favored by the Philadelphia City Planning Commission sought to interface with the state’s extension of the Turnpike at King of Prussia. To the delight of civic boosters, the City Planning Commission reported in 1950 that the state had “recognized that inter-regional highways connecting industrial and consumer centers can be fully effective in building up the economic vitality of the state.” Far from a leisurely parkway, the city’s new highways were designed to be people movers and catalysts for growth.

Although highway construction enjoyed popular support in the postwar years, topographic conditions, funding problems, and public resistance combined to make the Schuylkill Expressway one of the nation’s most idiosyncratic highways. Engineers cast the concrete ribbon through a landscape beset by natural and man-made obstacles, designing solutions that were unthinkable after standards set by the Federal Aid Highway Act of 1956. Engineer Bill Allen’s narrow stretch under 30th Street Station, the left-hand South Street Exit, and scant acceleration lanes are engineering curiosities which tell of the difficulty of building an urban highway on marginal space. The monumental traffic jams that formed at City Line Avenue when the first stretch of road was completed in 1949 foretold an ominous future. Clearly, the road was so attractive that “expressway” was a misnomer.

By the time the last stretch opened in 1959, Dilworth could boast of a new urban highway, the Roosevelt Expressway, and an embryonic mass transportation authority. But he could not forgive the road’s blunt incursion into Fairmount Park. Truly, Fairmount Park had been irreparably changed. Gustine Lake, a large public swimming hole in East Park near Ridge Avenue and City Line Avenue Bridge had been filled in for the aptly named “Gustine Lake Interchange.” Greenland Mansion in Fairmount Park stood right in the path of the Expressway – it would have sat right where the Greenland Road bridge now stands. Much sculpture was displaced and the large impervious surfaces of the road now affect the park’s watersheds. And the ever present drone of traffic interrupts the stillness. Allowing the road to bisect West Park was “the worst mistake in my Administration,” Dilworth later lamented.


  • Bauman, John F., “Expressways, Public Housing and Renewal: A Blueprint for Postwar Philadelphia, 1945-1960,” Pennsylvania History, Volume 57, Number 1, January 1990.
  • Clark Jr., Joseph S. and Dennis J. Clark, “Rally and Relapse, 1946-1968,” Philadelphia: A 300-Year History. Russell F. Weigley, ed. (New York: W.W. Norton, 1982), 695-698.
  • Conn, Steven. Metropolitan Philadelphia: Living with the Presence of the Past (Philadelphia: University of Pennsylvania Press, 2006), 176-178.
  • (Accessed October 17, 2007).

Urban Planning

The Broad Street Subway

Providing around 1 million rides a day, SEPTA is an important resource in the city of Philadelphia. The man pictured in one of the accompanying photos was just one of the many involved in building a part of that transportation system, the Broad Street Subway. The photograph was taken December 14, 1925 as the unidentified man worked on the subway at Broad and Master Streets.

Work began on the line in 1924. In the four years it took to build the initial section of the subway, enough dirt was excavated to theoretically create, as another photo (also pictured) illustrated, a column 220 feet square and 2280 feet high. The Broad Street line eventually opened for service on September 1, 1928. On this new subway, riders could travel between City Hall and Olney Avenue. Round trip fare, at this time, was only 15 cents.

Several years later, service on the Broad Street Subway was extended farther south. By 1930, riders could travel as far south as South Street, and by 1938 this was extended to Snyder Avenue. Expansion then continued to the north, with the Fern Rock stop being added in the 1950s. Finally, in 1973 the line was extended again to the south to run to Pattison Avenue, completing the line that exists today.