I have an odd question. Is AC power used to run locos? Is this common in Europe? What Manufacturers would use AC?
Thanks,
Mark
It depends on your definition of “run”. Some diesel engines use AC traction motors to drive the wheels. AC is the power of choice for catenary distribution for electricly powered engines and current engines probably are AC. The controls on both are probably DC duet to instrumentation requirements. I have no idea about Europe.
There have been AC locomotives for a long time - clear back to when PRR started hanging catenary, at least. The Northeast Corridor (or part of it) still uses that uncommon frequency (lower than 60hz) on part of its route.
Present-day Japan (including the HSR routes - strictly speaking, only Tokyo-Osaka is the Shinkansen) uses 25 kilovolt catenary at commercial frequency, except for some early installations that still run 1500VDC. The actual frequency is 50hz in Eastern Japan and 60hz in Western Japan, and there are locomotives that can operate under all three variants.
Chuck
Yes but Prr converted power to DC to the traction motors so technically not AC powered
Au contraire, PRR electrics running off the 25 Hz, 11,000V catenary used AC series motors exclusively up to about 1950 (well, the Big Liz was a phase converter job, but still AC).
- Erik
Modern locomotives take AC from the catenary through a step-dwon transformer or from an alternator (ac Generator) driven by the diesel prime mover, have it rectified to DC, then converted back to AC with the new frequency dpendent on speed and load conditions to power ac non-syncronous (slipping) hysterises semi-squeral-cage AC,motors. Some DC traction motor diesel-electrics are still built, but fewer in proportion every year if one does not count the rebuilding of old power for switching and short-line duty.
The E33 and E44s were “rectifiers”. They made DC from the AC out of the transformer and fed it to DC traction motors. But, before that - all AC.
The E33s and E44s were built after 1950… ISTR that PRR’s first rectified locomotive was built ca 1952.
- Erik
The PRR had a series of experimental locos in the early 50s.
The GE units were straight AC and the Westinghouse units were rectifiers.
They had cab style bodies, the GE were built by Alco and resembled FA1s and the Westinghouse were built by Baldwin-Lima-Hamilton and resembled Erie-builts - sort of.
Eric
Amtrak still uses 11K --25HZ traction power across the whole system. Everything else is tuned for that. Whould be a nightmare to change–and no reason to. Works fine
Amtrak electrics must also be able to work on 25 Kv and 60 Hz north of NY. It might be a nightmare to change, but if the old system “works fine” then why was ATK’s new construction, and MetroNorth and NJT’s reconstruction all 60 Hz?
NJT is also 21K and a new build in the 1980’s. Same Metro North. If you run from Boston MA to Washington DC–converting all those sub-stations—feeds not to mention signal system—WHY?–
Boston almost to NY already is converted.
Since Metro North NH line was rebuilt to 12 Kv 60 Hz, I assume if ATK rebuilt to 60 Hz, they would keep it also at 12 Kv in the NY terminal area for insulation clearance in tunnels, etc. However, south of there they are already replacing phase conversion substations as they fail, and they are having to replace 25 cycle transmission lines, which would be unnecessary if the converted to the standard 60 cycle. Eventually they will need to replace the cat with lightweight 25 Kv constant tension wire, in areas of high speed operation. As far as the signal system, will it need to be upgraded for PTC?
Signal system was being altered 2 yrs ago to handle the 160MPH capable Acela. Most they ever came by me was 135 but tested at higher. 100/25 HZ impedence bonds would all have to be changed out as well as some other signal equipment. Would be nice but not sure what their plans are anymore.
$$$ is an issue–as is manpower etc. There are interlocking in dire need of replacemment I agree on the constant tension and last I knew it was on the boards.
I think $$$ has always been the issue. In the early days Amtrak was assuming they would upgrade the NEC to 60 Hz. However, after they ran the numbers, they knew that they would not get the money, and instead repaired the system as necessary, and as you say, worked on interlockings and other more pressing problems. thus preserving the 25 cycle system a little longer.
I’ll defer to you on the traction power. I only handled switching/signal equipment.
Those lines carry 25 Hertz from the turbine at Safe Harbor dam. Over the years Amtrak has had to file a sort of “amicus brief” to keep the energy company from decommissioning the turbine, which costs more and more to maintain every year.
I found it quite odd that Amtrak elected to replace the two 25 Hz feeders, indeed, one of them is over a railroad right-of-way abandoned several decades ago. They must think that it was so over-engineered that, given the proper amount of maintenance, the turbine will survive indefinitely. The New York subway felt the same about their 60 Hz motor-generator DC converters which have similar engineering quality.
Well–I do know that on the New York Division–commercial 60HZ power comes in and is converted to 25HZ and 100HZ at the substations for Railroad use
I can’t speak for the canternary and rail feed locos of the NE USA. Main line locos from EMD and GE both ran on DC traction motors up to the time of the AC4400 and comparable EMD loco of the time period. Most Traction motors were rated at near 1,000 hp each. When I was hauling prime mover engines out of Grove City, Pa. I saw a 16 cylinder proto type test engine with a dual alternator being tested for 10,000 hp. These were to replace the 6000 hp engine then designed, but fuel economy won out and the new generation locomotive engines came to be.