25hz vs 60 hz traction system for amtrak

the part between Portal and New Haven will never see 25 Kv cause there is no structural clearance.
every viaduct, overpass would need to be raised about 2 feet.
cost would be multi-billion $$$

would be nice to see a long-term plan to convert from the 25 cycles to 60, say in the next 50 years. Are they going to wire the two new tunnels under the Hudson with 25Hz?

BandA wrote:would be nice to see a long-term plan to convert from the 25 cycles to 60, say in the next 50 years. Are they going to wire the two new tunnels under the Hudson with 25Hz?

Probably. But the wire hardware doesn't differ with the frequency so long as the voltage stays the same. If it's anything like when Metro North went from 25 Hz to 60 Hz on the New Haven Line + Hell Gate back in '84 it's a circuit-breaker changeout done phase break by phase break with no downtime except maybe night/weekend outages when they're doing the actual power change. The signal system runs at 100 Hz (low voltage) so the return current in the running rails and the track circuits aren't in conflict. Signal hardware is no different under 25 Hz AC, either 60 Hz AC voltage, or 750V DC third rail.


The only way the tunnels in/out of NYP will be changed to 60 Hz on any timetable less than deep- deep- long-term is if mythical Secaucus Loop gets built to drag LIRR and MNRR trains into Jersey. LIRR would be able to use its dual-mode locos because the North River Tunnels have (currently Sandy-damaged and turned off, but eventually repairable) 3rd rail, and LIRR's next MLV coach order will be able to fit through those tubes where their current C3's can't. They would just switch back to diesel mode at the tunnel portal. However, the only way you're getting future Penn Station Access trains on the New Haven Line into Jersey is either: A) laying another few miles of 3rd rail with couple more very expensive DC substations, or B) moving the 60/25 phase break to the other side of the river. The latter would be a hell of a lot cheaper, but there's that whole thorny jurisdictional issue of who's going to pay for a New York/Connecticut-operated commuter rail project that primarily benefits New Jersey (hence the "mythical" tag). So don't hold your breath on anyone at an executive level weighing those electrical pros/cons anytime soon.

Right, and even as expensive as custom rolling stock is, usually the wiring and electrical systems are more.

F-line to Dudley via Park wrote:..... LIRR would be able to use its dual-mode locos because the North River Tunnels have (currently Sandy-damaged and turned off, but eventually repairable) 3rd rail, and LIRR's next MLV coach order will be able to fit through those tubes where their current C3's can't....

Not sure where you heard C3's can't fit in the North River Tunnels, LIRR's dual modes and C3s are authorized in the tunnel with verbal permission from dispatcher for rescue purposes. As far as height goes they are cleared to operate anywhere on the NEC, but only authorized to operate the north river tunnels with special permission. Also 3rd rail is not turned off in the north river tunnels, again for rescue purposes in the event of an emergency. They will and have mobilized LIRR equipment to prepare for a rescue move (post sandy).

Part 1 -- History
PRR chose 25 Hz due to New Haven RR getting that frequency a couple years earlier. As well many manufacturing plants used that frequency at that time. So there were many electric generation locations that produced 25. PRR commissioned the Safe Harbor hydro plant to be the primary source for any rebooting of the system.( phase synchronizing ). PRR was buying CAT power in bulk so they chose to equip all their electrical needs using the 25 Hz. One exception was signal power that used 100 Hz ( still used by Amtrak in some locations ) that was provided by using frequency multipliers of 25 Hz.
PRR had all stations, back shops, motors, compressors, lighting etc using the 25 Hz. Some ancestors told this poster of lights dimming, flickering, so forth at times on the PRR. To this day some Amtrak location's electrical use is still 25Hz and unable to convert to 60 without major replacement and rewiring.

As power companies and plants realized the advantages of 60 Hz that allowed faster motor speeds and smaller transformers the demand for 25 Hz declined. This reduction naturally reduced 25 Hz generators until PRR had to install motor generators ( called rotary converters ) to convert from 60 Hz to 25. Siemens is now building solid state converters in north New Jersey. Note there was some flirting with 50 Hz but 60 prevailed in eastern USA. 50 Hz lasted on some west coast areas until after WW-2. Have a motor labeled for 50 / 60 Hz.

PRR started with nominal CAT voltage 11Kv +/- ~1000 volts. The high voltage transmission lines were 66Kv to ground on each leg much like your house' power for a total of 132Kv leg to leg.. Exception was west of Atglen Harrisburg line of 44Kv transmission lines. With fewer 25Hz generation locations PRR had a need for longer transmission distances. PRR boosted CAT to 11.5Kv sometime after WW-2 with transmission lines now nominal 135Kv. Sometime maybe after GG-1s retired Amtrak raised CAT voltage to 12Kv with transmission lines nominal 138KV. Note CAT nominal voltage is now +/- about 1200 Volts with transmission lines now approximately +/- 7200 volts.

Part 2
Mostly speculation history.
Reading RR followed PRR with 25Hz 11Kv CAT power. One small reason might have been RDG's at grade crossing of PRR's NEC line near North PHL and 16th street. Maybe RDG wanted to use some PRR MP-54s ? Other reasons unknown. If station services and other items used RDG's 25Hz is also unknown. If RDG ( later SEPTA ) increased its 25 HZ to 11.5 and 12Kv in lock step with PRR and Amtrak is also unknown. SEPTA is adding power capacity at Wayne junction with new frequency converters.
It is not know if the current exclusive SEPTA stations on both Amtrak and former RDG have any 25Hz still powering facilities.

Some SEPTA rolling stock equipment is reported to not be capable of 60Hz but have no confirmation

Exclusive MARC stations is unknown if ay 25Hz power although its Penn line is on Amtrak's NEC. All rolling stock 60Hz capable

NJ Transit might only have exclusive NEC stations and some stations still on 25Hz on the section of the Jersey coast line that still is 25Hz CAT.s All NJ Transit's rolling stock is reported as 60Hz capable and in contrast some EMUs of NJT have to be manually switched from 60 to 25Hz outside of train car.

east point wrote:Part 2
Mostly speculation history.
Reading RR followed PRR with 25Hz 11Kv CAT power. One small reason might have been RDG's at grade crossing of PRR's NEC line near North PHL and 16th street. Maybe RDG wanted to use some PRR MP-54s ? Other reasons unknown. If station services and other items used RDG's 25Hz is also unknown. If RDG ( later SEPTA ) increased its 25 HZ to 11.5 and 12Kv in lock step with PRR and Amtrak is also unknown. SEPTA is adding power capacity at Wayne junction with new frequency converters.
It is not know if the current exclusive SEPTA stations on both Amtrak and former RDG have any 25Hz still powering facilities.

Some SEPTA rolling stock equipment is reported to not be capable of 60Hz but have no confirmation

Exclusive MARC stations is unknown if ay 25Hz power although its Penn line is on Amtrak's NEC. All rolling stock 60Hz capable

NJ Transit might only have exclusive NEC stations and some stations still on 25Hz on the section of the Jersey coast line that still is 25Hz CAT.s All NJ Transit's rolling stock is reported as 60Hz capable and in contrast some EMUs of NJT have to be manually switched from 60 to 25Hz outside of train car.

The Arrows and Silverliner IV's still can't switch on-the-fly between 25 and 60. They can do each independently, just not while in motion the way all the locomotives can. But NJT issued the engineering contract for the MLV EMU's almost year-and-a-half ago so that RFP will be going out soon and replacement EMU's purchased within couple years, then bumping the Arrows in-service by 2020-22. Silverliner IV replacement TBD on procurement schedule, but probably same general time frame. Then nobody will be inconvenienced by any sections of 25 being fragmented by a gradual changeover to 60.

As a side note on the industrial use of 25Hz power, in 1971 I had an opportunity to tour the Bethlehem Steel plant at Bethlehem PA. At the time they were generating 25Hz power internally using generators powered by reciprocating engines driven off of blast furnace gas. A veritable industrial museum. I don't know if this generation lasted until he plant closure in 1995 but I suspect so given the financial state of BSC during that time period, they probably weren't putting much capital into the steelmaking operation.

Jon

As of right now, the only equipment not capable of the 25 hz/60 hz changeover on the fly, running between NYP and PJC, are the Arrow IIIs, and the only reason those are on the NEC at all is a tail-wagging-the-dog situation; EMUs would be a better fit on Midtown Direct services, with closer-spaced stations and lower ridership/train. So with minimal operational difficulty, the break in frequencies could be moved to somewhere west of SWIFT, or west of UNION if the NJCL is converted at the same time. That would take some coordination, but far less than required to convert the entire 25 hz system at once, and would begin paying operational dividends immediately. Of course, most of those benefits would accrue to NJT and NJT riders, which is the wrong set of incentives for an Amtrak project.

east point wrote:Part 2
Mostly speculation history.
Reading RR followed PRR with 25Hz 11Kv CAT power. One small reason might have been RDG's at grade crossing of PRR's NEC line near North PHL and 16th street.
It is not know if the current exclusive SEPTA stations on both Amtrak and former RDG have any 25Hz still powering facilities.

North Philadelphia (formerly Germantown Jct.) on the PRR over the Reading near 16th St. Jct. was not a grade crossing.
Logan Station on the Reading was able to use 100 volt, 100 cycle signal power if the Electric Company had a local failure.
Some accounts claim that PRR sometimes used 91-2/3 cycle Alternating Current for signals in 25 cycle catenary territory, so it wouldn't be an exact multiple of the propulsion current.

Cannot confirm this but read that the North river tunnels and east river tunnels use the 91-2/3 frequency for signals due to some kind of problem with the 600volt third rails. As to other locations ???

NY Penn was built with the 660VDC 3rd rail first,the 3rd rail network then extended to Manhattan Transfer in NJ from Sunnyside yard,
back then LIRR was a ward of PRR,and the 3rd rail extended eastward on the island.
The 11kv 25hz wire was added later,ending at Sunnyside Yard/Harold tower.
The NY Connecting RR a joint PRR/NHRR project,extended the NH Distrubution of 11 kv 25 hz power from Cos Cob over Hellgate Bridge
to Harold tower and Bay Ridge Float yard in Brooklyn.
There was never a known interconnect between the PRR and NH power grids.

Amtrak's 12kv 25 hz grid ends at a point(phase break) just east of CP Gate,MN's 12kv 60 hz grid powers the wire over Hellgate to New Haven at present.

Isn't MNRR 12.5Kv instead of 12Kv 60Hz ?

east point wrote:Isn't MNRR 12.5Kv instead of 12Kv 60Hz ?

Yes. Exactly half the voltage of generic world standard 25 kV used New Haven-Boston and on most of NJT's native electrification.