PRR Interlocking Diagrams: Philadelphia to Harrisburg Branches

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(If you're looking for the Chestnut Hill Branch or New Jersey Lines, they're on the New York page. The Gray's Ferry Branch is on the Washington page.

Schuylkill Branch

Starts at VALLEY (controlled by OVERBROOK) on the Harrisburg main line, proceeding north and west, closely paralleling the Reading RR mainline, to Reading and Pottsville. Connections were ultimately made with Reading and Lehigh Valley.

VALLEY, JEFF, MAN, Overbrook, Pa. (129K, 150 dpi)

Here the Schuylkill Branch turns northward, away from the main line. Several suburbian towns are passed before the branch crosses over the Schuylkill River on a high arch bridge (not shown on diagram) and enters Manayunk.

Norristown area, Norristown, Pa. (24K, 150 dpi)

CREEK, Oaks, Pa. (56K, 150 dpi)

An automatic interlocking within Manual Block territory, where the Schuylkill Branch crosses the Reading's Perkiomen Branch. Note the separate PRR and RDG spurs that join to enter the Alan Wood Steel Co.

Erasures on this diagram's left end include the block station at Phoenixville and two signals on either side of the track, where the word 'westward' is on this diagram. There is erased text below on the 1969 diagram indicating that the signal for eastward traffic, #7, is controlled from PHOENIXVILLE.

Are there any readers who may have run on this branch and who could explain what signal aspects would be seen at the 233 and 234 signals under what circumstances?

BROOKE, EAST BROOKE, WEST BROOKE, Birdsboro, Pa. (53K, 150 dpi)

Trenton Cut-Off

Forms a bypass around the Philadelphia area by connecting the main line northeastward to New York with the main line westward to Harrisburg.

Connection to MORRIS on the New York main line.

[32] MA, NICKEL, COPPER, MB, MY, Morrisville, Fallsington, Pa.

4283x1026, 60K, 200 dpi

Map 32 from New York division maps series.

[12] NEST, White Marsh Jct., Pa. [Earnest]

58K, 200 dpi
A later, Penn Central version (41K, 150 dpi)

Connection to Reading RR mainline between Philadelphia and Reading.

(There is no sheet 13.)
HS, CF, near Bridgeport, Pa., 191_?, (19K, 150 dpi)
[HS = Henderson Road; CF = ?] Interlockings near the middle portion of the Trenton Cutoff with then-new position light signals. Note that the position lights still had 4 lamps at that time. HS is almost certainly near Henderson Road, CF is in an unknown location. The Schuylkill River is between the two locations, flowing north to south (top to bottom as this map is oriented).

Connection to DALE, GLEN, and THORN on the Harrisburg main line.

Atglen & Susquehanna Branch

Starts at PARK on the Harrisburg main line. Forms a bypass around the hillier main line and Columbia Branch (see below). Used essentially exclusively by freight trains, and was one of at least two lines nicknamed "Low Grade". (The name was so pervasive that signals on this line had an "L" prefix.)

SMITH, near Quarryville, Pa. (42K, 200 dpi) [14]

PORT, CRES, Creswell, Pa. (40K, 200 dpi) [15]

Junction, southward, to the Columbia & Port Deposit Branch.

COLA, Columbia, Pa. (78K, 200 dpi) [16]

Columbia Branch joins in from the east. Both run (ran) together to ...

JEB, SHOCKS, Billmyer, Shocks Mills (Marietta), Pa. (46K, 200 dpi) [17]

Here the A&S and Columbia Br. part company. The A&S diverges slightly, then turns west, crossing the Susquehanna River on Shock's Mill Bridge, to Wago Jct. From Wago Jct. northward (RR-west) to Enola Yard, the A&S parallels the former Northern Central.

CLY, Cly (Goldsboro), Pa. (42K, 200 dpi) [18]

Bypasses LEMO interlocking, since here the A&S is at river level. Parallel former Northern Central tracks rise to the level of the Cumberland Valley Branch (former CVRR) bridge. See LEMO, sheet 19, under Cumberland Valley Branch, below.

DAY, Enola, Pa. (96K, 200 dpi) [20]

(There is no sheet 21.)

Enola Yard Eastbound Hump, Enola, Pa. (93K, 200 dpi) [48]

The sheet number is not in any obvious sequence.

Enola Yard Westbound Hump, Enola, Pa. (150K, 200 dpi) [49]

Connection to ROCKVILLE on the Pittsburgh main line.

(Sheet 25 is missing. Index lists it as "'PF-2' - Marysville Yd."


The uninitiated reader will be excused if he is is confused at this point. Quite obviously the PRR names are historical and did not necessarily reflect the routes most frequently traversed by trains in this century. Here are examples to help clarify:
1. Westward freight from Philadelphia to Enola:
Exits main line at PARK onto A&S Br. Passes through Quarryville and SMITH, turning north near river. Drops to PORT, ??? enters C&PD, remains on C&PD to COLA. Remains on A&S to SHOCKS, turns west across river, then north along river, to CLY. Here can either enter York Haven Line (Northern Central) through LEMO to DAY and Enola Yard, or stay at river level, bypassing LEMO, to DAY and Enola Yard. Conrail sensibly renamed this entire route "Enola Branch".
2. Eastward freight from Harrisburg Yard to Baltimore:
Exits main line at ROY onto Columbia Br. Passes SHOCKS and COLA. Enters C&PD at PORT and remains on C&PD all the way to PERRY on the Washington main line.

Columbia Branch

Starts at CORK on the Harrisburg main line. Proceeds westward through Mountville to Columbia, where it turns northward along the river.

Originally paralleled the A&S to SHOCKS, through the Chickies Rock tunnel, until abandoned (anyone know the year?). Presently trains enter A&S alignment.

Continues northward (RR-west) along the east bank of the Susquehanna, ending at ROY on the Harrisburg main line.

Northern Central (York Haven Line, York Secondary, etc.)

Starts at B&P JUNCTION tower, in Baltimore, on the Washington main line. (Note that the original NCRR also owned terminal trackage in Baltimore.)



Continues through CLY, LEMO, and DAY to Enola Yard - see A&S Branch above.

Lebanon Branch (or Secondary?)

Starts at Conewago on the Harrisburg main line, proceeding eastward and then northward.

[28] CORNWALL, Lebanon, Pa.

33K, 200 dpi
Crossing of the PRR Lebanon Branch with the Cornwall RR and Reading RR.

Cumberland Valley Branch

Starts at STATE on the Harrisburg main line.

[19] LEMO, Lemoyne, Pa.

5743x2055, 168K, 200 dpi
After crossing the Susquehanna River, the CV Branch crosses over the A&S Branch on a bridge, then over the NC Branch at grade, before proceeding west (RR-south) through Lemoyne and Camp Hill toward Shiremanstown, Mechanicsburg, Carlisle, and Newville. Electrification extended west of the diamond into the small yard. This was geographically the farthest west that electrification extended in Pennsylvania; I believe that Washington, D.C. is a bit farther west overall.

Connections via former Northern Central northward to DAY and Enola Yard and southward to CLY and York, Pa.

(Sheet 20 is DAY tower. There is no sheet 21.)

[22] PENNROAD, Shippensburg, Pa.

4923x1049, 70K, 200 dpi
Interlocking and passing siding, as well as connection to Reading RR Lurgan Branch. After passing through town on street trackage, the CV Branch passes under the Lurgan Branch and turns southward, accepting the connection from the Reading. The map shows additional trackage as far south as Chambersburg, about 12 miles. The next 15 miles or so are not shown.

Connection northward (CVRR-east; PRR-east; RDG-east) to Reading RR Lurgan Branch.

[23] TOWN, Hagerstown, Md

6661x1025, 79K, 200 dpi
Crossing of the Cumberland Valley Branch with the Western Maryland main line, just RR-east of the Hagerstown yard. At this location, too, the WM Lurgan Branch cuts off northward, with the Baltimore main proceeding to the lower right of the diagram.

[24] HAGER, Hagerstown, Md.

3129x1054, 50K, 200 dpi
Crossing of the Cumberland Valley Branch with the Western Maryland at one of the (timetable) western ends of the WM Hagerstown yard. The WM main west to Cumberland is not seen on this diagram; rather, this is a separate section of the yard, not far from the engine terminal, that connected to CVRR and SVRR (Norfolk & Western). The CV Branch continues southward from here toward Winchester, Va.

Connection southward to Norfolk & Western Vardo Yard.

(There is no sheet 25.)


These don't neatly fit in a given Division or Region, since the boundaries moved too much and too often (especially after the 1940s), so I gathered them here.

Bradford Hills, Bradford Hills, Pa. (30K, 200 dpi) [29]
A later, Penn Central version. (20K, 150 dpi)

A very simple crossing of the PRR and RDG, illustrating the use of STOP signs on the railroad.

Chester Valley intersection, Downingtown, Pa. (32K, 200 dpi) [26]
A later, Penn Central version. (22K, 150 dpi)

Another PRR-RDG stop-sign-protected crossing.

Mark's Railroad-Related Stuff
The Broad Way: A Pennsylvania Railroad Home Page
Maps of the PRR
Interlocking Diagrams
Philadelphia to Harrisburg: Branches and Yards

Mark D. Bej
+1 216-444-0119