Guide to Landforms Seen Along SEPTA’s Warminster Regional Rail Line

Authors

Overview: Along its 21-mile distance SEPTA’s Warminster Regional Rail line ascends from sea level to approximately 320 feet and crosses the Delaware-Schuylkill River drainage divide twice as it travels from the Tookany Creek drainage basin to the Wissahickon Creek drainage basin and then to the Pennypack Creek drainage basin. Along the way observant riders can see the Coastal Plain Province-Piedmont Province boundary, observe metamorphic rock exposures as the train travels to and through the Tookany Creek gorge, note a well-defined wind gap carved into a high quartzite ridge at Ardsley, and travel in the valley of a barbed Pennypack Creek tributary before ending their trip in a region underlain by Triassic age shale, mudstone, and sandstone

City Center to Fern Rock Station: After leaving Jefferson Station the rail line turns in a north direction as it climbs out of the tunnel (which at Jefferson Station is approximately at sea level) and rises above street level providing good views on both sides to reach the elevated Temple University Station. From Temple University to the North Broad Station the tracks are above street level, but at the North Broad station the tracks descend to below street level and are in a trench as streets and other rail lines are located overhead. After leaving the trench the tracks are again above street level to Wayne Junction Station (elevation approximately 100 feet above sea level) and then almost all the way to the Fern Rock Station (elevation approximately 120 feet above sea level).

For the entire distance between the City Center and Fern Rock Station the track is located on the Coastal Plain Province, although from Wayne Junction Station to Fern Rock Station the track is located along the boundary between the Coastal Plain Province (to the southeast or right) and the Piedmont Province (to the northwest or left). No Coastal Plain landforms or bedrock exposures can be seen as urban development has completely altered surface features that once were present. Coastal Plain Province bedrock if it could be seen is marine or fluvial sedimentary material deposited on a basement of metamorphic rocks with the sedimentary rocks generally thickening in a seaward direction.

When the train is approaching the Wayne Junction Station a low tree-covered ridge is visible to the northwest with higher elevations along the ridge crest being 230 or more feet above sea level. This ridge marks the Piedmont Province southeast boundary. This ridge is particularly noticeable after the SEPTA rail line crosses Hunting Park Avenue and a freight rail line just before passing a large SEPTA maintenance complex. The freight rail line was built in a shallow northeast to southwest oriented valley that the railroad deepened further so as to pass under streets and the SEPTA line tracks. The shallow valley in which the freight rail line is located was eroded by southwest oriented water flowing to the Schuylkill River valley. Just before reaching the Wayne Junction station the SEPTA rail line turns in a northeast direction so as to continue along the boundary between the Piedmont and Coastal Plain Provinces to the Fern Rock Station.

Fern Rock to Melrose Park: After leaving the Fern Rock Station the track enters the Piedmont Province and while not obvious from the train is climbing to an elevation of slightly over 200 feet above sea level as it passes through several cuts where bedrock exposures can be seen from the train window. The bedrock here is the Wissahickon Formation of probable early Paleozoic age, which is composed of metamorphic rocks that represent the roots of a former mountain range. Similar rocks are buried beneath the Coastal Plain Province marine and fluvial sediments, although in the Piedmont Province the metamorphic rocks stand higher in elevation and the marine and fluvial cover is not present. Reasons why the metamorphic rocks stand higher in the Piedmont Province region have been debated in the geologic literature, although many geologists consider the Coastal Plain-Piedmont Province boundary to be an erosional feature.

Melrose Park to Elkins Park: The Melrose Park Station has an elevation of approximately 200 feet above sea level with a hill to the northwest rising to approximately 250 feet while a Tookany Creek tributary valley can be seen to the northeast. The Piedmont Province surface in this region has been eroded by east and northeast oriented Tookany Creek tributaries and after leaving the Melrose Park Station the train passes through a cut as it crosses the ridge between two such tributary valleys before reaching the Elkins Park Station. The rail line between Melrose Park and Elkins Park maintains its elevation at close to 200 feet above sea level.

Elkins Park to Jenkintown: After leaving the Elkins Park Station the train passes over Old York Road (Route 611) and then closely follows Tookany Creek, with the creek being first located to the east (right) and then switching to the west (left). The rail line elevation at Elkins Park is slightly below 200 feet above sea level, but rises to slightly more than 200 feet at Jenkintown. South-flowing Tookany Creek crosses the 200-foot contour line a short distance south of the Jenkintown Station. While not easy to visualize the trip between Elkins Park and Jenkintown is made at the bottom of a V-shaped valley with elevations to the east at Jenkintown rising to more than 340 feet and elevations to the west rising to more than 400 feet. The water-eroded valley is carved in the Wissahickon Formation metamorphic rock complex, which underlies the entire region. Bedrock exposures are visible along both the rail line and the stream channel. This rock cut valley or gorge was eroded by large quantities of water, probably much more water than the present day Tookany Creek drainage basin could possibly produce. Evidence for routes water used to flow from other drainage basins into the Tookany Creek drainage basin is seen just beyond Jenkintown, north of Glenside, and at Ardlsey Station.

Jenkintown to Glenside: The Jenkintown Station is located in the deepest section of the Tookany Creek gorge with elevations in Jenkintown to the east rising to approximately 340 feet and elevations along the Tookany Creek-Wissahickon Creek drainage divide to the west rising to more than 400 feet. Yet immediately after leaving Jenkintown Station there is a major rail junction with the SEPTA West Trenton Rail Line turning to the northeast while the Warminster and Lansdale Rail Lines turn to the northwest. While not obvious from the Warminster and Lansdale trains the West Trenton Rail Line is located in a deep through valley linking the Pennypack Creek valley to the east with the Tookany Creek valley at Jenkintown. The through valley floor on which the West Trenton Rail Line is located has an elevation of approximately 220 feet at the Tookany-Pennypack Creek drainage divide (near Noble Station). Large volumes of southwest oriented water moved in that through valley to reach the Tookany Creek valley. The through valley is also remarkably straight, which has led some geologists to suggest it follows a fault line.

Also just north of the Jenkintown Station there is a significant change in the Tookany Creek direction of flow. Between Jenkintown and Elkins Park Tookany Creek flows in a south direction and south of Elkins Park becomes Tacony Creek and then Frankford Creek before flowing into the southwest oriented Delaware River. Just north of the Jenkintown Station the Warminster (and Lansdale) Rail Lines as they turn to the northwest cross the south-flowing Tookany Creek channel, however a short distance further just before the Rice’s Mill Road grade crossing the rail lines again crosses Tookany Creek and at that second crossing the creek is flowing in an east direction. Tookany Creek originates as an east oriented stream and flows through Glenside to the Jenkintown rail junction location and then turns to flow in a south direction through the Tookany Creek gorge., Once across the east oriented Tookany Creek headwaters segment the Warminster train leaves the Tookany Creek valley and enters a wide southeast oriented tributary valley to reach the Glenside Station.

Glenside to Ardsley: After leaving Glenside Station the Warminster train begins to climb before reaching the rail junction where the Warminster Rail Line turns in a northeast direction while the Lansdale Rail Line continues in a northwest direction. While not easily seen from the Warminster trains the Lansdale Rail Line crosses the Tookany Creek-Wissahickon Creek drainage divide at a wind gap (deepened by a railroad cut) just a short distance to the northwest. That wind gap was eroded by southeast oriented water flowing into the Tookany Creek valley prior to erosion of the Wissahickon Creek drainage basin to the north and northwest. The Lansdale Rail Line elevation where it crosses the drainage divide is approximately 320 feet while high elevations along the Edge Hill quartzite ridge into which the wind gap is notched exceed 430 feet

From the rail junction just beyond the Glenside Station the Warminster train proceeds in a northeast direction up the narrow valley of a southwest oriented Tookany tributary with the Edge Hill quartzite ridge to the northwest (left) and a 340-foot high hill and then the head of a southeast and southwest oriented valley seen to the southeast. Ardsley Station is located on the floor of another wind gap notched into the Edge Hill quartzite ridge and is at an elevation of about 320 feet. Both the Warminster Rail Line and Jenkintown Road cross the Edge Hill ridge at the Ardsley wind gap and unlike where the Lansdale Rail Line crosses the Edge Hill quartzite ridge there is no evidence at Ardsley that the wind gap floor has been manually deepened. Edge Hill ridge elevations east of the Ardsley wind gap rise to more than 430 feet suggesting the Ardsley wind gap is at least 100 feet deep. The Ardsley wind gap is located on the Wissahickon Creek-Tookany Creek drainage divide, which is also the Schuylkill River-Delaware River drainage divide.

Ardsley to Roslyn: After leaving the Ardsley Station the Warminster train continues in a northeast direction on the northwest side of the Edge Hill quartzite ridge. The rail line and the large cemetery to the northwest are located in the drainage basin of Sandy Run, which flows to south oriented Wissahickon Creek with water then flowing through the deep Wissahickon Creek gorge to reach the Schuylkill River. The Warminster rail line maintains an elevation of between 300 and 320 feet while Edge Hill quartzite ridge to the southeast rises to more than 430 feet. At and beyond Roslyn Station there are good views of the wide Sandy Run valley to the north and of the Camp Hill quartzite ridge to the north of the valley. Bedrock making up the valley floor is limestone, which is more easily eroded than the quartzite making up the bounding ridges. While today it is difficult to imagine, the wide valley did not exist at the time the Ardsley wind gap was eroded. At that time the entire region was at least as high the present day quartzite ridge tops and water was eroding the Ardsley wind gap as it flowed in a southwest direction from what is now the Sandy Run headwaters to the Tookany Creek drainage basin. Flow through the Ardsley wind gap ended when limestone bedrock between the quartzite ridges permitted headward erosion of the Sandy Run drainage basin to capture the southwest flow.

Roslyn to Crestmont: From Roslyn Station to the Crestmont the Warminster Rail Line continues at an approximate elevation of 300 feet above sea level in a northeast direction along the northwest side of the high Edge Hill quartzite ridge and there are some excellent views of the wide Sandy Run valley to the north. Crestmont Station is located where the Warminister Rail Line turns slightly away from the Edge Hill quartzite ridge to cross the Sandy Run headwaters valley.

Crestmont to Willow Grove: After leaving Crestmont Station the Warminster train climbs to an elevation of approximately 320 feet as it enters a deep cut in a 350-foot high ridge that forms the Sandy Run-Pennypack Creek drainage divide (which is also the Schuylkill River-Delaware River drainage divide). There is no evidence that a wind gap once existed at the cut location although slightly to the north there is a shallow wind gap that prior to headward erosion of the Pennypack Creek drainage basin was probably eroded by southwest oriented flow. Note in the cut how the bedrock is no longer the metamorphic rock complex seen between Fern Rock and Jenkintown, but is instead layered sedimentary rock. The rocks have been tilted since they were originally laid down as horizontal sedimentary beds, which is evidence mountains once existed here . Once through the cut the rail line enters the head of a northeast oriented tributary valley.

Willow Grove to Hatboro: At the Willow Grove Station the track is still at an elevation of almost 300 feet above sea level, but on leaving the Willow Grove Station the track descends as it follows the valley of a northeast oriented Pennypack Creek tributary. Views of the tributary can be seen to the left (or northwest) until the track turns to the north so as to cross the tributary and to continue to descend into the Pennypack Creek valley. The northeast oriented tributary is interesting as Pennypack Creek flows generally in a south direction to reach the Delaware River, which means the tributary flows in the opposite direction of the stream it joins (making it a barbed tributary).

After the tributary has been crossed notice how the bedrock exposed in cuts along the tracks is red in color. The Warminster train has now crossed from an area underlain by older and usually harder to erode Paleozoic and possibly older metamorphic and sedimentary rocks into a region underlain by easier to erode and sometimes red in color, shale, mudstone, and sandstone of Triassic age. Once in the Pennypack Creek valley a sewage treatment plant is on the right (east side of track) and the track follows Pennypack Creek for a short distance before crossing the stream at an elevation of approximately 200 feet above sea level before beginning to climb out of the valley to reach the Hatboro Station, which has an elevation of about 240 feet above sea level.

Hatboro to Warminster: From Hatboro to Warminster the train continues to travel over Triassic shale, mudstone, and sandstones and landscape features are much less pronounced than earlier on the trip, although the train gradually gains elevation as the Warminster Station is approached. The Warminster Station has an elevation of approximately 320 feet above sea level and is almost at the same elevation as the Ardsley wind gap through which the train previously passed. Before erosion of the Pennypack Creek valley it would have been possible for water flowing in a southwest direction across the Warminster area to reach and flow through the Ardsley wind gap and then to enter the Tookany Creek valley where such water would have helped to erode the Tookany Creek gorge seen between Elkins Park and Jenkintown. Headward erosion of the Sandy Run drainage basin would have captured the water flowing through the Ardsley wind gap and diverted that captured water to Wissahickon Creek, which would have helped to erode the Wissahickon Creek gorge. Finally headward erosion of the Pennypack Creek valley would have next captured the water, which then would have helped to erode the Pennypack Creek valley downstream from the Hatboro area.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: