Corridor Electric Power Generation and Distribution

[PRRTechFan]

Gilbert B Norman wrote:

...no power for the Corridor is generated at Conowingo?

I have been unable to locate information on Conowingo to the level of detail that I found for Safe Harbor; like number and type of turbines, generators, transformers, electrical ratings, etc. "Single phase" and "25hz" of course are the tip-offs...

[prr60]

Conowingo Hydro Electric Project, built by Philadelphia Electric in 1927, does not have any dedicated 25hz generators. Only Safe Harbor has that distinction. Nor does Conowingo have any specific power arrangements with Amtrak.

However, since Amtrak contracts with PECO Energy (the "modern" name for Philadelphia Electric) for power, and since PECO has long term power supply contracts with its unregulated affiliate, Exelon Generation (now the owner of Conowingo), it can be said that Amtrak does get some power from that dam along with the nearby Exelon-owned Muddy Rum pump-storage dam.

[Gilbert B Norman]

Of interest to our discussion

http://www.shwpc.com/default.asp

The ride along the Columbia & Port Deposit to me is one of the most scenic in the Northeast and passed both dams; during the years of 1974 & 75, I had occasion to make several trips on the Broadway Ltd, which during that era had its Wash section so routed.

The line was electrified and if there was a track speed anywhere on the line of 40mph, I'd like to know where. But the likelihood of riding over such today, save being an NS operating employee, is limited to fan trips when or if they will operate in the future.

I'm not certain when the PRR last operated a passenger train over the C&PD, but it was long before A-Day. The traditionall PRR Wash Chicago route (Liberty Limited) was via the Northern Central through York, PA.

Of further interest, the PRR and successors had always purchased electric power; Phila Electric was a major supplier. This is in contrast with the New Haven that generated much of its own at a Cos Cob, CT plant (replaced today by condos that are likely "in the ones') . As for the importance that later day New Haven managements placed on that facility, I think I speak for any of us "New Haven hands' around here by saying "let's not go there..." (maybe Mr T will entertain that discussion at his New Haven Forum....and maybe he might not!!!!).

But enough of these off topic digressions.

[Jersey_Mike]

More info. Baltimore Gas and Electric owns four 138kV transmission circuits between Conestoga and Perryville. PRR apparantly did not own the transmission between those points; BG&E must have built and owns it under contract for PRR/Amtrak. That would explain why it looks like a conventional utility transmission tower structure, except that to the practiced eye, there would be 2 wires per circuit, not 3. A total of 8 circuit wires if there are 4 circuits on the structures.

Well, a single phaze system dosen't need 2 wires, just one. BTW, I heard that Philly and Chicago still used a 2-phaze system. Is this true?

Anyway, I found some better photographs on that same roll

http://acm.jhu.edu/~sthurmovik/Railpics ... RY-4SA.jpg

There's the clincher. 4 pairs of transmission lines comming off a commercial tower. 2 pairs head south, 2 north. In theory the north pairs can be out of phaze with the south pairs, but although the PB's are still in service, I think that Amtrak keeps all the SH turbines in phaze.

Hard to believe that commercial tower is over 70 years old. The design is sort of ageless if you catch my drift.

Hey, question. Who powers the former PRR electrified segment of the NYLB? I know that NJT changed the newly electrified section from 25 to 60Hz, but don't know what's up with the PRR segment. As a follow on, are the transmission lines along the Jamesburg branch still utilized for anything?

Shame that Amtrak let Conrail cut down the line along the Trenton Cuttoff...i hear they could use the extra capacity now.

I hope one day to get into the Power Dispater's room at STATE. See how things really work. Shame Conrail had to wus out and pull the plug on electrification, this was quite an amazing system. A private PRR power grid.

[David Benton]

Single phase needs 2 wires for transmission, active and neutral (return ) . Only in very remote areas is the earth used as a return , and certainly not for high amperage applications like railroad traction . Its just too inefficent .

[Jersey_Mike]

Single phase needs 2 wires for transmission, active and neutral (return ) . Only in very remote areas is the earth used as a return , and certainly not for high amperage applications like railroad traction . Its just too inefficent .

Most people's home's are on Single phaze and they all use the ground as a return. Don't most AC systems use ground return?

[David Benton]

The neutral line is usually bonded to earth , but the power should only flow through the earth in a fault condition .
i dont know the system used in USA households for sure , but i would be very surprised if they didnt have a phase ( live ) , a neutral ( return ) , and a earth wire in most wiring .
Earth cannot match the low resisitance of copper or aliminuim wires , hence there are quite high losses in an earth return only system . It is used here in very remote areas with few consumers , where the cost of the second wire would make the intial capital cost too high .

[Ken W2KB]

The neutral line is usually bonded to earth , .

You are correct, David. The third (neutral) wire to a building is used for the return, to the extent the load is not balanced on either 120 bus. It is bonded to the ground at the service entrance to avoid a voltage differential. The other critical reasons are that earth return is problematic as (1) there are serious issues with stray voltages that can injure or kill, and (20 the return flow would often use gas and water mains and similar for its return path, which results in galvanic action and corrosion. This was a constant problem for trolley companies since the return rails were buried in the earth and the return current would divide and a portion flow back in pipes.

[Ken W2KB]

Hey, question. Who powers the former PRR electrified segment of the NYLB? I know that NJT changed the newly electrified section from 25 to 60Hz, but don't know what's up with the PRR segment. As a follow on, are the transmission lines along the Jamesburg branch still utilized for anything?

The NYLB is supplied from JCP&L for transmission service. I have no idea what power contracts may exist. Also don't know who are the power suppliers for Amtrak. Could be any marketer/broker, or an assortment. PECO used to be the main supplier but that may no longer be the case if others have outbid PECO.

The transmission on the Jamesburg branch would serve no purpose unless the lines connect back into the main line at some point, thus forming a loop that could be used for a backup. I suspect that it is radial and thus not used, probably no longer energized.

[PRRTechFan]

The 132kV, 25hz single phase transmission lines are 2 wire circuits, and both wires are "hot" with respect to "ground". The circuits are derived from transformers with center-tapped windings, and the center-taps are resistance grounded to provide a ground reference so the system does not "float" at an unknown potential above ground. The resistance grounding permits the system to continue in operation in the event of a single "ground"; and it also allows for "ground detection" when that fault occurs.

Under normal circumstances, the wires in the transmission "pair" would read 132kV from line to line and 66kV from line to ground. The two 66kV lines, being single phase, are 180 degrees out-of-phase with each other so the voltages "add" to 132kV.

Almost the same thing happens in your home. The utility transformer has a 240 volt center-tapped winding, and the center-tap is grounded for redundancy and for safety so the circuit does not "float". But in this case, the current-carrying neutral wire is also connected to the transformer center tap and brought into your home panel, and all of your 120 volt circuits are derived between one of those two "240 volt" hot wires and neutral. The 240 volt circuits for A/C or pump motors come from the two "hot" conductors.

JCP&L feeds the NY&LB with a huge substation in Matawan. I believe the substation and associated transmission line (230kV?) were constructed primarily for NJT traction power when electrification finally came south of Matawan. JCP&L has existing substation facilities in Red Bank (remember the brownout/blackout at the shore several summers ago? THAT substation...); and although there is a phase break south of the train station, I do not know whether another feed is taken from the Red Bank sub.

The 25hz ex-PRR electrification was originally extended from South Amboy to Matawan. As Jersey_Mike indicated, some of this appears to have been converted to 60hz, no doubt extended north from the Matawan sub. I noticed on a recent trip that there was a new "phase break" just north of the Morgan Drawbridge; my guess is that this is where the 25-60hz changeover now takes place.

As for the Jamesburg Branch, I believe that all of the actual 13kV catenary from there east towards South Amboy was de-energized and removed quite a while ago. However, the 132kV transmission lines remained a while longer. When the Rt. 18 bridge was replaced over that branch, they re-routed and installed new towers for these lines. But the 132kV was eventually cut. You can still see the towers and insulators from the Garden State Parkway where it crosses over the branch just south of the Raritan River tolls... (...Or the remnants of the northbound tolls, anyway...)

Too bad that 132kV line is gone; it was a backup to the transmission line from the substation at UNION that came down and crossed the Raritan River bridge to feed the last 25hz substation at South Amboy. If I recall, a barge crane took out that line several years ago, halting service on the NJCL. If the 132kV line through Jamesburg was still in service, service could have been restored by opening and closing a couple of disconnects. Ah, redundancy!

[Jersey_Mike]

JCP&L feeds the NY&LB with a huge substation in Matawan. I believe the substation and associated transmission line (230kV?) were constructed primarily for NJT traction power when electrification finally came south of Matawan. JCP&L has existing substation facilities in Red Bank (remember the brownout/blackout at the shore several summers ago? THAT substation...); and although there is a phase break south of the train station, I do not know whether another feed is taken from the Red Bank sub.

But is the old PRR segment between UNION and ESSAY is still powered by Amtrak? As you said the PRR transmission lines still connect the substation in South Amboy so it appears that is still the case.

[Jtgshu]

The Coast Line between Union and Essay is probably powered partially by Amtrak, to a point, but there is a large Substation in South Amboy - up the Essay Running track and to the west of the main tracks - thats why the Essay running track is still catenary powered, and active, and the main lines go up that way -- im sure NJT has a payment agreement, just like on the NEC of how much power each train uses, and is charged accordingly - they probably do the same thing to Essay, except that they don't have to sort out the NJT trains and the Amtrak trains.

The barge at River took out maybe power lines, but the main problem with that was it ripped down the signal wires for the signal system - if the line was still controlled by towers, it would have been fine (at least for diesels if the power was interrupted) - but all access and controls to the signals was severed by that crane.

There is a substation at Matawan, by the GSP bridge - the electrification to Matawan is as far as Conrail could extend it without a new substation (from South Amboy). that substation in Matawan, from what I understand, powers from Aberdeen to Laural Phase break, while the substation in the former Red Bank yard controls from Laural to Red Bank phase Gaps ,while the substation in Long Branch next to the yard controls from end of wire to Red Bank phase gap.

The new "phase break" at Morgan is apprently due to the condition of the catenary over the moveable bridge - previously, AFAIK, engineers had to put the throttle in Idle anyway while crossing over - someone probably didn't and shot the line and scared the beejesus out of the operator on the bridge, so they put the phase gap in.

Sort of back on topic i guess, it is truely amazing to me the amount of power that goes through the lines, and especially on the NEC, how old the infrastructure is, and even though it does have problems sometimes, its pretty darn reliable - there are probably more electric trains, and drawing more power from teh infrastructure than any time in its past - Too bad there aren't any G's flying down at 100mph, but seeing an ALP46 flying down at 100mph with a 10 or more (if Amtrak) train in tow is also pretty impressive!!!

[Ken W2KB]

JCP&L feeds the NY&LB with a huge substation in Matawan. I believe the substation and associated transmission line (230kV?) were constructed primarily for NJT traction power when electrification finally came south of Matawan. JCP&L has existing substation facilities in Red Bank (remember the brownout/blackout at the shore several summers ago? THAT substation...); and although there is a phase break south of the train station, I do not know whether another feed is taken from the Red Bank sub.

Good description. My utility transmission system map shows two radially fed substations hung on the JCP&L 230kV system. One is labeled "NJT Aberdeen" and the other "NJT Red Bank."

[Ken W2KB]

Sort of back on topic i guess, it is truely amazing to me the amount of power that goes through the lines, and especially on the NEC, how old the infrastructure is, and even though it does have problems sometimes, its pretty darn reliable - there are probably more electric trains, and drawing more power from teh infrastructure than any time in its past - Too bad there aren't any G's flying down at 100mph, but seeing an ALP46 flying down at 100mph with a 10 or more (if Amtrak) train in tow is also pretty impressive!!!

Sure is. I even have some old records from the mid-1960's where the conversion of the NEC to 60Hz was being studied. And then the resurrected studies at the time NJT decided to go 25kV on the M&E, after which the Federal NEC funding fell through. So the existing system has lasted 40 years since the earlier plans to update it!

[Jersey_Mike]

FYI Amtrak also provides power on the former PRR SEPTA R3 and R8 lines and through the CC Tunnel.

Hey, does anyone know how the power works on the former Reading system works? The Reading dosen't seem to have much in the way of high tension transmission so does each Substation have a converter on site?