I'm confused by the third-rail shoe. Amtrak says it's selling "direct-drive gas turbine" Turboliners which evidently means the engine powers the wheels through hydraulic transmission and gears, not using an electric generator. So, then, what is the third-rail shoe powering? Were these trains rebuilt to be electric-driven or something? Are different generations of Rohr Turbliners diesel-electric and others hydraulic and gear-driven?
Grand Central Terminal was accessed by something called the Park Avenue Tunnel. Inside the train shed and in the tunnel, making any kind of engine fumes is forbidden by law. All trains using Grand Central have had some form of electric propulsion with enough power to get trains in and out of the station.
Metro North is the commuter line operating out of Grand Central, and they get their power from a third rail, or at least for the runs closer to the city -- as with the LIRR out of Penn Station, the outlying runs may have Diesels, again, with the ability to run on electric power inside the tunnel.
The United Aircraft TurboTrain that preceded it along with the Rohr Turboliner had third rail shoes and small traction motors to allow electric operation where it is required. The FL-9 Diesels along with the dual-mode Genesis units already have traction motors so all they need are the pickup shoes and associated switch gear to change from Diesel to all-electric modes.
The United Aircraft TurboTrain used a number (I believe 5 for traction, 1 for hotel power) of small turbines, adapted from helicopters. The power was taken off a second-stage "free turbine" that kind of acted as a gas-drive torque converter, and then transmitted mechanically through gear boxes, shafts, and Cardan (universal) joints to the axles. I say "kind of" because I understand that a fluid torque converter is more efficient owing to the higher density of hydraulic oil over air at transmitting power at different speeds. The Turbotrain had only a pair of somewhat larger turbines, one in each power car at the ends of the train, and it used a proper hydraulic torque converter.
Some of this was discussed on an earlier thread too.
When Amtrak ordered the Turboliner, a "TurboTrain II" was in competition with it. The United Aircraft offering called "TurboTrain II" was described by an article in Aviation Week of all places. TurboTrain II was supposed to have only a single turbine in each power car and a proper torque converter, just like the French-derived TurboLiner, and TurboTrain II was lighter in weight, but the fuel consumption numbers (largely dominated by aerodynamics and the turbine part-load operation) were roughly the same, and Amtrak had maintenance concerns about TurboTrain II.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Yes, Paul, since the tunnel is beneath Park Avenue, from 97th Street on south, it is called the "Park Avenue Tunnel."
Except for the few trains that run through between Wassaic and NYC, and New Canaan and NYC (inbound in the morning, and outbound in the afternoon), MU equipment is used. (I think I am right in saying that the runs that end at Brewster North {now called "Southeast"} and at New Haven are all MU). The trains that run through must have the dual-power. Incidentally, Metro-North uses leased Amtrak engines for the diesel-only trains north of Southeast and Stamford, and South Norwalk (for Waterbury). The dual-power engines may also be leased from Amtrak. Also, the MU equipment used to and from New Haven is equipped with both overhead and third-rail pickup–there is no overhead power in the tunnel or in the train shed in NYC. Wait, there used to be, and still may be, 600 (or thereabouts) volt DC wire overhead because of the many switches in the approach to the station. MU trains should not have a problem with the gaps in the third rail since they are long enough to span the gaps. The old NH engines, at least, had small pantographs for this use.
Likewise, all trains that come into Penn Station (and any other underground operation in Manhattan) must have electric power. Thus, the engines used between NYC and Rensselaer are dual-power.
Johnny
aegrotatio I'm confused by the third-rail shoe. Amtrak says it's selling "direct-drive gas turbine" Turboliners which evidently means the engine powers the wheels through hydraulic transmission and gears, not using an electric generator. So, then, what is the third-rail shoe powering? Were these trains rebuilt to be electric-driven or something? Are different generations of Rohr Turbliners diesel-electric and others hydraulic and gear-driven?
All the Rohrs were mechanically driven and had a single traction motor for third rail operation. The traction motor would power the mechanical drive system when the turbine had to be shut down in GCT and under Park Ave. (Later, it was needed in the short, new tunnel from Penn Sta to the ex-NYC West Side.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Ahh, the third-rail shoe powers little auxiliary traction motors.
So the dual-mode diesel-electric conventional locomotives, do all of them have auxiliary traction motors, too? I am wondering about the voltage difference in powering from 3rd rail as opposed to the diesel generator as well.
Thanks for the information!
aegrotatioSo the dual-mode diesel-electric conventional locomotives, do all of them have auxiliary traction motors, too? I am wondering about the voltage difference in powering from 3rd rail as opposed to the diesel generator as well.
See Paul Milenkovic's post at 4:21 pm ET on 2-23. Any actual difference in the voltage from the third rail and from the diesel-powered generator was insignificant. With the FL-9's and the Genesis locomotives that were/are operated underground on Manhattan the same motors were/are used, whether the electricity is generated on board or is picked up from the third rail.
Third rail voltage isn't quite high enough to get an FL9 to full speed on it's own. A DC main generator can do about 900VDC, the third rail is typically 600-700VDC. The FL9s had some really serious field shunting on them!
oltmannd Third rail voltage isn't quite high enough to get an FL9 to full speed on it's own. A DC main generator can do about 900VDC, the third rail is typically 600-700VDC. The FL9s had some really serious field shunting on them!
DeggestyExcept for the few trains that run through between Wassaic and NYC, and New Canaan and NYC (inbound in the morning, and outbound in the afternoon), MU equipment is used. (I think I am right in saying that the runs that end at Brewster North {now called "Southeast"} and at New Haven are all MU).
Except for the few trains that run through between Wassaic and NYC, and New Canaan and NYC (inbound in the morning, and outbound in the afternoon), MU equipment is used. (I think I am right in saying that the runs that end at Brewster North {now called "Southeast"} and at New Haven are all MU).
I believe you meant Danbury instead of New Canaan as New Canaan is still served by MU, usually a shuttle running between New Canaan and Stamford.
erikem I believe you meant Danbury instead of New Canaan as New Canaan is still served by MU, usually a shuttle running between New Canaan and Stamford.
Yup it was the voltage and current differences I was looking for. Thanks for the information. It's interesting to me that using third rail outside the tunnels is almost completely ruled out for Metro-North locomotives that use NYC tracks.
And I just realized why the ACES train has an electric on one and and diesel on the other. There is not a dual-mode catenary-powered diesel yet.
However, the LIRR dual-power locomotives can provide full speed on third rail as opposed to those for Metro North. The LIRR dual power locomotives have alternators, and dc is suppled by electronic conversion, diodes, etc. On the LIRR, but probably not Metro North, and certainly not on the FL-9's except possibly for the totally rebuilt "Starship" models, the DC is converted to AC, which then can be transformed or handled electroniclly to be the same voltage as the AC from the alternator, and then is converted to whatever the traction motors require at their speed and power requirements. Up to this point I have my facts straight, but I am uncertain whether the LIRR locomotives have AC or DC motors. I think AC.
The LIRR dual mode locomotives are AC propulsion - that's the key to their 3rd rail performance. A DC propulsion unit, whether it has a main generator or traction alternator with diode rectifier would have the same 3rd rail voltage limitations as an FL9.
Okay! I was going to ask about why LIRR has great 3rd-rail performance and you hit the nail right on the head. Thanks!!
The Turboliner Power Cars do not have "lttle traction motors" A 300 HP Metroliner traction motor drives the Voith 411 Bru hydraulic transmission through an over-running clutch on an auxiliary shaft. (The original Metroliner cars were Multiple Unit types capable of 160 mph service. When these were converted to locomotive hauled coaches, the traction motors were removed and were thus available for the Turboliner function.) The the NYC Fire Commisioner ruled many years ago that no coal fired nor internal combustion power could be used for traction in the tunnels into Grand Central and Penn Station. Amtrak interpreted the "traction" limitation narrowly and ran the Turboliners 400 kW gas turbine powered auxiliary power units in the tunnels. Anticipating that they would not be able to do this on the RTLIII Turboliners, 700 VDC inverters were specified to provide auxiliary power in the tunnels. The Third rail system, which runs for only 7 minutes on each trip, costs more than the primary turbine hydraulic system.
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