Passenger Trains > Surviving PRR-style phase break signals?

I've always thought that the PRR position light phase break indicator signals are among the most unusual RR signals out there (eight lamps in a "star" arrangement), and I want to take a proper photo of one before they disappear completely.

I have an older (ca. 1998) Amtrak employee timetable that list them as being at three locations in electrified Amtrak territory:
- East of Bergen (just past the North River tube in NJ) on the NEC
- at Perry (Perryville, MD) on the NEC
- at the Thorndale substation (just before the Thorndale SEPTA station) on the Harrisburg line

I believe I've also seen a set of them on the SEPTA main line 9th street viaduct just north of the Philly Center City tunnel (which, if I'm correct, I presume are relatively new).

Are any of these still actually there? Are any located in a where they can be photographed without suicidal trespassing? (I suppose asking for ones that are regularly actually illuminated may be asking too much, too late).

Thanks

Metro North also installed one east of Devon Junction in ex-New Haven territory, but I don't know if it's still there, and getting at it would be, um, a challenge.

Also between Rye and Harrison, just west of Playland Parkway.

nm2320 Wrote:
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> Also between Rye and Harrison, just west of
> Playland Parkway.


Is that an actual position light indicator, or just a phase break? Is it in a position to be photographed without superpowers or risk of death?

Thanks

The Metro-North one at Harrison is located in the middle of the cantenary structure spanning the four track main, is not easily accessable and would be serious tresspassing.

IIRC the best one to photograph would be the one at Thorndale. It is located on the northside cantenary post and could be shot from along side the parallel highway with a long lens without tresspassing.



Edited 1 time(s). Last edit at 04/09/10 10:40 by PPLX777.

PPLX777 Wrote:
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> The Metro-North one at Harrison is located in the
> middle of the cantenary structure spanning the
> four track main, is not easily accessable and
> would we serious tresspassing.
>
> IIRC the best one to photograph would be the one
> at Thorndale. It is located on the northside
> cantenary post and could be shot from along side
> the parallel highway with a long lens without
> tresspassing.

Excellent -- thanks!

For a Californian far from AC powered trains, what is a phase break signal? (I assume it is where a train goes from one power block to another and the two are not in phase with each other, but that's just a (probably wrong) guess.)

joemagruder Wrote:
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> For a Californian far from AC powered trains, what
> is a phase break signal? (I assume it is where a
> train goes from one power block to another and the
> two are not in phase with each other, but that's
> just a (probably wrong) guess.)


Yes, that's right. The PRR had several different power plants, which were not always in phase. The phase break signals were located at the boundaries between sections served by different plants. When the indicator is on, engineers of electric locomotives / MU trainsets had to take special precautions to ensure against bridging the two sections (in some cases this involved lowering the pantographs before coasting through the gap section).

I managed to detour through Perryville this afternoon on my way to DC, and found the phase gap signal bridge. Mission accomplished.

---

mab Wrote:

> Yes, that's right. The PRR had several different
> power plants, which were not always in phase. The
> phase break signals were located at the boundaries
> between sections served by different plants. When
> the indicator is on, engineers of electric
> locomotives / MU trainsets had to take special
> precautions to ensure against bridging the two
> sections (in some cases this involved lowering the
> pantographs before coasting through the gap
> section).

The phase break sections consist (in sequence) of a catenary fed by one powerplant, a "middle" catenary, and then the catenary fed by the second powerplant. If the first and second powerplants are in-phase, then the middle catenary is connected to one of them and that means that there is continuous overhead power available to the train through the "phase break" section.

If the equipment detects that the first and second powerplants are not in phase, then it automatically disconnects the middle catenary and lights the indicator. Operationally, this means the train will become de-energized for a short period as it coasts through the de-energized middle catenary region. I believe the purpose of the phase-break indicator is to alert the train crew to this.

Normal operation:

Catenary A Middle Catenary Catenary B
-----------+----------------> <----------------

Operation when Catenary A and Catenary B are out of phase:

----------> <---------------> <----------------

Thanks for the explanation.

There's a short phase gap on the connections at SWIFT in Kearny, NJ, the connector between the NEC and the Morristown Line. The Morristown line is on the new electric, Amtrak is on the old PRR electric. For perhaps two seconds, the lights go off, and the air conditioning goes off. Then it pops on again. I believe it's a 25 mph speed. so the gap might be 40 or 50 feet, I'm guessing.

The gap inbound in the morning doesn't seem as long, but I'm sure it is.

There's a phase gap warning sign track side.

Lackawanna484 Wrote:
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> There's a short phase gap on the connections at
> SWIFT in Kearny, NJ, the connector between the NEC
> and the Morristown Line. The Morristown line is on
> the new electric, Amtrak is on the old PRR
> electric. For perhaps two seconds, the lights go
> off, and the air conditioning goes off. Then it
> pops on again. I believe it's a 25 mph speed. so
> the gap might be 40 or 50 feet, I'm guessing.

Don't know how long the phase gap is as Swift, but the connection is good for 70MPH, not 25. Not that they do 70 often, but I've been on many trains that are easily doing 60 through the junction.

There's also a phase gap on NJT's Morristown line (M&E) between South Orange and Maplewood.

Rob Benkovitz
Short Hills, NJ

rbenko Wrote:
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> Lackawanna484 Wrote:
> --------------------------------------------------
> -----
> > There's a short phase gap on the connections at
> > SWIFT in Kearny, NJ, the connector between the
> NEC
> > and the Morristown Line. The Morristown line is
> on
> > the new electric, Amtrak is on the old PRR
> > electric. For perhaps two seconds, the lights
> go
> > off, and the air conditioning goes off. Then
> it
> > pops on again. I believe it's a 25 mph speed.
> so
> > the gap might be 40 or 50 feet, I'm guessing.
>
> Don't know how long the phase gap is as Swift, but
> the connection is good for 70MPH, not 25. Not
> that they do 70 often, but I've been on many
> trains that are easily doing 60 through the
> junction.
>
> There's also a phase gap on NJT's Morristown line
> (M&E) between South Orange and Maplewood.
>
> Rob Benkovitz
> Short Hills, NJ

Good point.

The difference in speed could certainly explain the difference in the length of lights / AC off on various trips.

FWIW, Montclair trains usually take that segment slowly. As they take the rest of their trip, too.