Major Investment Study / Draft Environmental Impact Statement   3. Conceptual Engineering, Operations Analysis, and Costs

3.1.3 ELECTRIFICATION

3.1.3.1 TECHNICAL ASPECTS - ELECTRIFICATION

The R6 Cynwyd line is fed by a larger power system, which also supplies Amtrak's Northeast Corridor and Harrisburg Line, as well as the other SEPTA lines on the Pennsylvania Railroad side of the Regional Rail system. The catenary is energized at 12 kV AC at 25 Hz from a substation located near the Zoo. No additional substations feed the Cynwyd line.

The two power systems - that of the former Reading Railroad lines, and that of the former Pennsylvania Railroad lines - are separate systems, and while both have overhead catenary energized at 12 kV AC at 25 Hz, the two systems are not in phase and operate independently. They are separated by a phase break north of the Center City Commuter Tunnel on the Reading side.

For electrification to Reading (Wyomissing), it is recommended that a 60 Hz power system be adopted. This will eliminate the need for 25 Hz distribution conductors and/or additional static frequency converters to convert power from the industrial power grid (60 Hz) to 25 Hz for the catenary. Equipment on modern rolling stock allows operation under both 25 Hz and 60 Hz catenary, as is currently practiced on Amtrak's Northeast Corridor. The equipment can switch automatically between the two systems. 

Thus, the existing infrastructure to Norristown could be maintained at 25 Hz and the extended electrification would be constructed using 60 Hz power with substations supplied directly by the industrial grid. The final number of substations required depends on a more detailed analysis to be performed during subsequent engineering stages of the project. At 12 kV AC electrification, typical substation spacing is approximately 10 miles. The option exists, however, to electrify at 25 kV AC, which would allow for approximately twice the distance between substations. Similar to multi-frequency operation, modern train equipment can switch between different voltages on the same line. Another factor to consider is the level of system redundancy in case of a substation failure or planned outage. More substations provide greater redundancy. A trade-off analysis should be performed during the Preliminary Engineering stage of the project.

3.1.3.2 ELECTRIFICATION - COMMUTER RAIL ALTERNATIVES 

Philadelphia to Norristown - From Norristown to Philadelphia the following electrification work is proposed. For Alternatives 1D and 1E, no changes to the power supply system of the R6 Norristown Line are proposed. The light rail shuttle operating from Ivy Ridge to Center City via the Cynwyd line, Girard Avenue, the City Branch, and city streets would be electrified at 600 V DC matching the existing light rail (trolley) system. On the new portions of the line, a trolley type overhead contact system would be constructed. On the portion consisting of the existing Cynwyd line, however, the catenary structures would be used and converted for low voltage DC electrification, consisting primarily of adding feeder cables to provide higher current capacity. Existing shop and yard facilities would be utilized for this line, thus requiring that the electrification system and vehicle power pickup be compatible with the existing city trolley system.

For Alternative 2D, no changes to the electrification system of the R6 Norristown Line are proposed. On the Cynwyd Line the catenary on the abandoned sections of track would be restored to Ivy Ridge and new catenary constructed past Ivy Ridge to the new connection with the Norristown line. The Cynwyd line would continue to be supplied by the Amtrak power distribution system with a phase break located between Manayunk and Ivy Ridge to keep the two systems independent.

The extension of SEPTA's Route 100 (NHSL) will use third rail electrification (630 V DC) identical to that on the existing line. Power will be supplied from the existing line and from a new substation on the extension.

3.1.3.3 ELECTRIFICATION - LIGHT RAIL ALTERNATIVES

Philadelphia to Norristown - Alternatives 5E and 5ET would be electrified with a 600 V DC Overhead Contact System from their Center City terminals to west of the Zoo station on the light rail segment. On Girard Avenue the OCS would be shared with Route 15 trolleys and will require the modification of the existing trolley wire throughout the shared section to be capable of accommodating both trolley pole and pantograph operation. West of the Zoo Station, the dual-power light rail cars will switch to a high voltage 12 kV 25 Hz overhead contact system. New catenary would be constructed to 52nd Street and the catenary on the abandoned part of the Cynwyd line would be restored to Ivy Ridge. New catenary would be constructed west of Ivy Ridge to the connection with the existing R6 Norristown tracks. Additionally, no changes are proposed on the existing R6 Norristown line, which would now be terminated at Ivy Ridge; it would continue to be supplied by the Wayne Junction frequency converter and substation.

The power supply to the light rail alignment between the Zoo and Norristown spans two existing independent systems, the Amtrak power distribution system serving the Cynwyd Line, and SEPTA's autotransformer system out of Wayne Junction, which feeds the Norristown line. Different options exist to provide power to the light rail line. The existing systems could be used as they are today with a phase break located between Manayunk and Ivy Ridge to keep them independent. This would result in a 25 Hz AC system all the way to Norristown for light rail. An alternative to utilizing the existing power supply systems between the Zoo and Norristown is the conversion to a 60 Hz supply system identical to that proposed for the new portions of the line west of Norristown. This would require the construction of up to two additional feeder substations supplied directly from the industrial grid but would eliminate the need for the light rail vehicles to be capable of switching between 25 Hz and 60 Hz AC, which may provide some savings in vehicle cost. It would also decrease the power demand on the Wayne Junction frequency converter and on the Amtrak power distribution system, thus possibly reducing the need for future capacity expansion of those systems to meet service growth as planned by SEPTA and Amtrak. A more detailed analysis should be performed during the Preliminary Engineering phase of the project to determine if the 60 Hz conversion on the existing portion of light rail alignment for Alternatives 5E and 5ET would be cost effective.

From Center City to Norristown, Alternative 6 would operate using the existing traction power system in place on the R6 lines (12kV 25Hz). No changes are proposed on the Norristown line. The Cynwyd line catenary would be restored over the abandoned tracks to Ivy Ridge and new catenary would be constructed from the Ivy Ridge Station to the connection with the Norristown line. Since the Norristown line and the Cynwyd line are served by the two independent, and not in phase, traction power systems, a phase break would be placed between Manayunk and Ivy Ridge to maintain system independence. Beyond Norristown, Alternative 6 would use high voltage (12kV or 25 kV) 60 Hz electrification as described above.

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