Pennsylvania Historic Preservation

Blog of the Pennsylvania State Historic Preservation Office

Evaluating Pennsylvania’s Railroads for National Register Eligibility


As all railroad history buffs know, Pennsylvania played an important role in the growth of the industry and has a great abundance of remaining stations, tunnels, bridges, and tracks. 

Pennsylvania became the national leader in railroad development in the late 19th century.  By 1860 it held more miles of railroad tracks than all other states. It continued to lead the nation in railroad use well into the 20th century.   

To better understand the significance of the many railroads which crisscrossed the state, the PA SHPO has compiled data about individual railroad lines for National Register evaluation.

Railroads in PA

Railroads in Pennsylvania grew from about 2,600 miles of track in 1860 to peak at 11,693 miles of track in 1920. During that period of growth railroads dominated the transportation industry and were constructed throughout the state to serve a variety of needs. Small and large railroads to serve specific industries and areas were established with mergers and leases of tracks adding to complexity of railroad history.    

Gaining an understanding of the complicated, changing and often interconnected world of railroads required the development of a SHPO strategy for study.

To date there are approximately 343 railroad lines or segments of railroad lines that have been surveyed in Pennsylvania. Only a few railroad lines have been surveyed in their entirety.   Many individual railroad related resources such as stations, bridges and tunnels have been surveyed as well, but most have not been evaluated as part of the railroad line associated with them. 

Due to the fragmented past survey efforts and the ongoing challenge of evaluating such a vast network of railroad related properties, the PA SHPO created the “Aggregate Railroad” records to gather information about specific railroad lines and connect related resources from different geographic locations under one historic property file/key number.

Pennsylvania Railroad – Schuylkill Valley Division System Map showing previous determinations of eligibility; multiple surveyed sections of a railroad line, PA SHPO Key File # 124898. Survey form prepared by AECOM in 2009.

What is an Aggregate Railroad?

The Aggregate Railroad files were intended to organize railroad data so that researchers could better understand the history and significance of individual railroad lines and place railroad resources within that context. Using a common key file number provides a link in CRGIS to connect these related railroad resources.   

Many Aggregate Railroad files have very limited survey information about the overall significance of the line and few detailed reports about related contributing features.  Nonetheless these digital files are linked in CRGIS and show up in reports due to their common historic association with a particular railroad line as shown in the CRGIS report screen.

Philadelphia & Reading Railroad Aggregate Key # 155708, Associated Resources screen, PA SHPO CRGIS.

By linking resources related to a specific railroad line to a common Key number, the PA SHPO created a means to understand surveyed components of the rail line, even when they may exist over a broad area.   

The Aggregate Railroads file approach was the best way to link and associate all of the hundreds of individual survey records using our CRGIS system. Currently, all of the SHPO key number files have been scanned and made available online via the CRGIS system

What was the Aggregate Railroad Update?

The initial purpose of the update was to standardize the documentation of railroad related resources for use in the PA SHPO files and the CRGIS mapping system.  In an effort to reconcile the expansive railroad related data collected over many years from project submissions, the PA SHPO hired contractors to assist in an information gathering effort to better define the Aggregate Railroad files.

A methodology for the update was created to ensure the collection of all readily available information on the history of railroad lines as well as the presence or absence and current appearance of associated resources in Pennsylvania. The following sources were consulted and information was compiled into inventory sheets for each of the aggregate railroads:

Railroad resources in the PA SHPO’s Key files using a CRGIS search 

Railroad company’s annual reports and/or Henry V. Poor’s Manual of the Railroads of the United States.  Both of these sources are available online via either Internet Archives or Google Books. As primary documents, they contain a historical sketch, termini and description of the line and its branches, construction of bridges and stations, and other details.

Poor’s Manual of Railroads of the United States, 1894 (Volume 27, page 42), from

The Pennsylvania Railroad Stations Past & Present website which provides a searchable database of railroad stations by name and county. The website provides historic and current photographs when available, as well as location information. 

Snapshot from the Pennsylvania Railroad Stations Past & Present website,

Online information related to railroads posted by Rails to Trail organizations or found on municipality websites. Sometimes trail visitors post photographs of railroad tunnels or bridges along former railroad tracks that have not been documented in PA SHPO files and images that are not available via online aerials.

Cynwyd Station Revitalization, Lower Merion Historical Society “Milestones” December 2013. From

PennDOT historic roadway bridge survey completed in 2001 and available online on PennDot’s Historic Bridges website as roadway bridges were built by railroads or the Commonwealth to facilitate railroad/roadway crossings and thus are historically associated with the railroad line.

Historic American Buildings Survey (HABS) and the Historic American Engineering Record (HAER).  The National Park Service used the services of both HABS and HAER to document large or significant bridges in the 1980s and beyond.  Photographs and historic drawings from those efforts are available online in the Library of Congress Prints and Photographs Division collection.

Philadelphia & Reading Railroad, Susquehanna River Bridge, Harrisburg, Dauphin County. Library of Congress, Prints & Photographs Division HAER, HAER PA-523,

Google and/or Bing aerials. Aerial images of both modern and older bridges along a railroad corridor can be useful in creating an inventory of related bridges noting style, construction type and number of modern bridges.

USGS Mapping, Central Railroad of New Jersey, PA SHPO Key 155754, PA SHPO CRGIS.
Aerial (Google) image, Central Railroad of New Jersey, PA SHPO Key # 155754, PA SHPO CRGIS layer.
Central Railroad of New Jersey Bridge, Catasauqua PA, Streetview, Google Maps, 2019.

The Aggregate Railroad Update resulted in the collection of detailed information on the history and remaining features for 53 railroads. The information collected as part of the update was compiled into inventory sheets. For each railroad, the inventory sheet includes a timeline of development; history; primary resource documentation; and the location, name, type, and photographs of resources along the line.

How will the transition to PASHARE affect Aggregate Railroad Key files?

 In January 2021 the PA SHPO is transitioning to a new electronic system called PA-SHARE.  In order to make a smooth transition of data from our current CRGIS to this new system, the aggregate file system will cease to exist. 

Instead, a new way of linking surveyed resources and connecting them with existing and new data will be put into place.  The goal of this new approach will be to seamlessly integrate existing railroad line data with new data. Using the materials gathered in the Aggregate Railroad Update, when new data is received, the SHPO will be able to provide a determination of eligibility for an entire railroad line.

What are the next steps for former Aggregate Railroads?

The PA SHPO is removing the naming convention of “Aggregate” from the 53 records in CRGIS. Railroads will continue to exist as linear historic districts in PA-SHARE. PA SHPO staff will be uploading the inventory sheets as well as the methodology for the Aggregate Railroad Update to each railroad.

In 2021, SHPO staff will use the inventory sheets  and existing guidance for evaluating railroads  “Guidelines for Documentation and Evaluating Railroads” to assess the National Register eligibility of the former Aggregate Railroads.

Comments, information and suggestions regarding the railroads in Pennsylvania are always welcome and appreciated by PA SHPO staff.  

Author: Cheryl Nagle

Cheryl has been with the PA SHPO since 2007. She started out in the National Register section, and is currently the Above Ground Resource Environmental reviewer for the Western Region.

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