RVRR 15 wrote:
I noticed you left out a part of the Genesis locomotive name, that being the P42DC. AC traction motors have contributed greatly to higher wheel horsepower. (Note the AC6000, on the freight side of things.)
AC or DC motors makes no difference on the horsepower. Sure, it might mean a different torque curve, but there have been plenty of high HP DC motors out there, along with plenty of high HP AC ones. A 100 HP electric motor is 100HP, regardless of it being DC, AC, wound rotor, synchronous, asynchronous, series wound, shunt, repulsion, etc. It's 100HP, period.
Ok, one place where AC does make a difference - on a diesel locomotive, you now have to add your inversion losses to the transmission losses. DC's actually very slightly more efficient, but AC allows far better control, so you get better overall TE.
BTW, DB's class 103 locomotives of the late 60's had a short time rating of 10,000 HP, and were DC machines (thyristo rectifers, though they were tap changer units, as phase angle control at that time couldn't meet DB's requirements).
And in any case, i was comparing NJT's <b>PL</b>-42 to their ALP-46. The PL-42's an AC unit with an EMD prime mover. I'd expect a GE powered unit to be even slower, since GEs take forever and a day to load, for some reason known only to GE...
Not to mention, you are not citing alternate (higher) gearing, and focusing on the status quo. (Did you forget that the P42DC operates on the Northeast Corridor in revenue service?)
Gearing means virtually nothing on AC units. With IGBT inverters and today's more advanced controls, the difference in TE between a 125mph locomotive and a 100mph one is trivial (if it even exists). Besides, the actual HP delivered at the rails by any of the current US passenger diesels is so low, that it's not even worth bothering to achieve higher speeds, especially with the overweight trains this country runs. Amtrak's '110mph' track in NY state is a cute thing, but the reality is that with any train longer than a 4 or 5 cars, the train spends so little time at 110mph, it's not even worth it. Even the Acela's much flaunted 150mph running is so insignificant in the grand scheme of things, that it shaves barely a minute off the schedule over 125mph running.
You are omitting facts. All of the EMD and GE diesels sold for export of late have been drag freight types, and there are no passenger diesels in the catalog.
Of course they're drag units. They're unsuited for passenger service. Today's modern passenger operations demand accelerations far higher than US equipment can achieve, period.
The countries that buy such freight diesels usually operate DMUs on non-electrified lines.
Of course they do. They don't want their lines clogged up by passenger trains that can't get out of their own way. And since most diesel lines are feeders to larger mainlines (inevitably electric), they need to be small trains, and they need to have electric-compatible performance. At one time in the last few years, the fastest multiple unit out there was, in fact, a diesel. Modern DMUs such at the Stadler GTWs, offer performance that can't be touched by a locomotive hauled train, with a far lower noise and emissions footprint. Of course, EMUs today are a bit faster, as power electronics have gotten better/lighter/smaller/more powerful - Stadler's FLIRT can go from a standstill to 90mph - in under a minute.
Furthermore, you are not clarifying what you mean by "high-speed passenger service". Without giving us a benchmark, you are speaking into the air.
Last I checked, the UIC standard was 125mph (220km/h) and up. Only the FRA thinks going faster than 80mph (140km/h) is 'high speed', nobody else does.