Transmission Lines
All transmission lines within the 25 Hz system are two-wire, single-phase, 138 kV. The center tap of each 138 kV/12 kV transformer is connected to ground, thus the two transmission lines are tied to ±69 kV with respect to ground and 138 kV relative to each other.
Generally two separate two-wire circuits travel along the rail line between substations. One circuit is mounted at the top of the catenary poles on one side of the track; the second circuit runs along the other side.
The arrangement of catenary supports and transmission wires gives the overhead structure along former Pennsylvania Railroad lines its characteristic 80-foot-tall 'H'-shaped structure. They are much taller than the overhead electrification structures on other electrified American railroads due to the 138 kV transmission lines. Catenary towers and transmission lines along former New York, New Haven and Hartford Railroad lines and Amtrak's New England division are much shorter, and are recognizable due to different design and construction.
While a majority of the transmission infrastructure is located directly above the rail lines on the same structure that supports the catenary system, some lines are either located above lines that have been de-electrified or abandoned or in a few cases on completely independent rights of way.
The following is a list of all major segments of the 25 Hz 138 kV transmission infrastructure listing substations (SS or Sub) or high-tension switching stations (HT Sw'g) as termini. For clarity, positions of substations are not repeated in this table. A listing of the high-tension switching stations follows.
| Terminus | Terminus | # 138 kV circuits | Right of way | Notes |
|---|---|---|---|---|
| Union City Sub 42 | Cornwell Heights Sub 32 | 4 | Main Line Philadelphia to New York | |
| Kearney Sub 41 | Journal Square Sub 50 | 2 | Jersey City Branch | Out of service, line used by PATH. |
| Rahway Sub 39 | South Amboy 48 | 2 | Jamesburg Branch | Used for NJTRO NJCL power |
| Monmouth Jct 36 | South Amboy 48 | 1 | Jamesburg Branch | Via Helmetta Sub 47; Out of service, lines removed. |
| Morrisville Sub 34 | Earnest HT Sw'g | 1 | Trenton Cutoff | Out of service and almost completely removed. Some portions east of the Earnest Junction HT Switching Station and west of the Morrisville Substation (within the confines of the Morrisville yard) remain. |
| Cornwells Heights Sub 32 | Richmond Sub 31 | 2 | Industrial RoW | Splits from Main Line south of Holmesburg and follows alignment along Delaware River. |
| Cornwells Heights Sub 32 | Richmond Sub 31 | 2 | Along Main Line to Frankford Junction, then Delair Branch | |
| Frankford Sub 30 | Richmond Sub 31 | 2 | Delair Branch | 12kV catenary removed. |
| Cornwell Heights Sub 32 | Frankford Sub 30 | 1 | Along Main Line RoW Phil to NY | |
| Frankford Sub 30 | Ivy City Sub 25 | 2 | Main Line from north of Phil to Washington | |
| Zoo Sub 9 | Earnest HT Sw'g | 2 | Schuylkill Branch | Tracks removed past Cynwyd Station. |
| Arsenal Sub 2A | Lenni Sub 02 | 1 | West Chester Branch | Power for SEPTA Media/Elwyn Line. |
| Lamokin Sub 11 | Lenni Sub 02 | 1 (2) | Private RoW | Feeds west end of SEPTA Media/Elwyn Line. Built as two (c. 1935) circuits. |
| Earnest HT Sw'g | Frazer Sub 64 | 2 | Runs along Trenton Cutoff | Powers Main Line via Frazer Sub |
| Paoli Sub 4 | Landisville Sub 69 | 2 | Main Line Philadelphia to Harrisburg | Frazer SS to Paoli SS dead end line. |
| Parkesburg Sub 66 | Safe Harbor Sub 55 | 2 | Atglen and Susquehanna | Rails removed. Catenary poles removed and transmission lines replaced in 2010/2011. See section below. |
| Landisville Sub 69 | Royalton Sub 71 | 1 | Main Line Philadelphia to Harrisburg | |
| Safe Harbor Sub 55 | Rowenna Sub 57 | 2 | Enola Branch | After Rowenna Sub decommissioned, one circuit logically split to run direct to Royalton Sub. |
| Rowenna Sub 57 | Royalton Sub 71 | 1 | Royalton Branch | Line now continuous from Safe Harbor to Royalton. |
| Rowenna Sub 57 | Lemo HT Sw'g | 1 | Enola Branch | Out of service, then removed 2011. |
| Lemo HT Sw'g | Enola Sub 59 | 2 | Enola Branch | Served at Enola Yard, then removed 2011. |
| Royalton Sub 71 | Harrisburg Sub 72 | 2 | Main Line Philadelphia to Harrisburg | |
| Lemo HT Sw'g | Harrisburg Sub 72 | 2 | Runs across Susquehanna River on Cumberland Valley RR Bridge | Out of service |
| Safe Harbor Sub 55 | Perryville Sub 16 | 4 | Private RoW | Utility-style transmission towers. P5 and P6 lines were tapped south to serve Fishing Creek Sub 54 and Conowingo Sub 53. These taps were removed concurrently with their associated substations. |
| Landover Sub 24 | Ivy City Sub 25 | 2 | Main Line Philadelphia to Washington | Portion from Landover (24) to Ivy City (25) constructed in 2010. |
| Landover Sub 24 | Capitol (Former Sub 25) | 2 | Landover Line | Former route to Capitol Sub 25. Out of service and partially removed. |
| Name | Location | Designation | Comments |
|---|---|---|---|
| Metuchen HT Sw'g | 40°32′56″N 74°20′47″W / 40.548998°N 74.346318°W / 40.548998; -74.346318 (Metuchen HT Sw'g) | 138M through 438M | Disconnects each of main line circuits (4) from two spurs that runs via private ROW to Metuchen Frequency Changer. |
| Lemo HT Sw'g | 40°14′54″N 76°53′19″W / 40.248454°N 76.888483°W / 40.248454; -76.888483 (Lemo HT Sw'g) | West of Susquehanna River near Harrisburg; disconnects circuits running between Enola, Harrisburg, and Rowenna substations | |
| Earnest HT Sw'g | 40°6′15″N 75°19′15″W / 40.10417°N 75.32083°W / 40.10417; -75.32083 (Earnest HT Sw'g) | 163,263 (Trenton Cutoff E); 164, 264 (Trenton Cutoff W); 1ED,2ED (to Zoo) | Located at junction between Trenton Cutoff and Schuylkill Branch. Manually operated disconnect switches, now redundant with the abandonment of Trenton Cutoff transmission line and removal of Earnest Sub 63. |
| Frankford HT Sw'g | 40°00′05″N 75°05′39″W / 40.0013°N 75.0943°W / 40.0013; -75.0943 (Frankford HT Sw'g 22) | 22 | Disconnects the feeder (42H) from Richmond from transmission line running between Frankford (22HT) and Cornwells (230E) in event of damage to catenary supports on Delair Branch. Allow limited feeding between Cornwells and Frankford to bypass Richmond. |
Read more about this topic: Amtrak's 25 Hz Traction Power System
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