Back in the era when the universal locomotive was all the rage, French state railways SNCF and its biggest supplier, then called GEC-Alsthom, bet on the wrong technology. On one hand, they still believed that one motor per bogie (i.e. two wheelsets) is more economic (less maintenance). On the other hand, they went for the synchronous AC motor. That was good enough for second-generation TGVs, but, while the power of the DB class 120 could be matched at the time, asynchronous AC motors had a higher potential.
Back in the era when the universal locomotive was all the rage, French state railways SNCF and its biggest supplier, then called GEC-Alsthom, bet on the wrong technology.
On one hand, they still believed that one motor per bogie (i.e. two wheelsets) is more economic (less maintenance). On the other hand, they went for the synchronous AC motor. That was good enough for second-generation TGVs, but, while the power of the DB class 120 could be matched at the time, asynchronous AC motors had a higher potential.
To which I should add: a variation on the synchronous AC motor (in which the magnetic fields and the rotor rotate at the same speed, i.e. synchronously), the so-called "permanent magned synchronous motor", is actually the Next Big Thing. And just Alstom is the leading developer.
The permanent magnet motors are even more efficient, and that on a much wider rotational speed range. While the practical difference in efficiency is miniscule (say 95% vs 98%...), the permanent magnet motor can do without gears: meaning, it can be built around the wheelset axle (resp. hollow shaft), a direct drive. (Again the parallels with wind power technology...) Sparing the gears also means further weight reduction.
Here is an illustration íi found for a Siemens application, with the traditional motor-gears-wheel on the left and a new direct drive on the right:
As yet, the permanent magnet motor is only used in lighter trains (the top use being in Alstom's AGV high-speed train). For scale: the AGV's motors are rated at 760 kW, while state-of-the-art asynchronous AC locomotive motors are rated at 1600 kW. But, I'd expect permanent magnet motors in a heavy-duty locomotive to come in the next decade. *Lunatic*, n. One whose delusions are out of fashion.
Indeed that's a question -- but, given how asynchronous AC pushed out wound-field DC, I don't think it's impossible if the technology becomes mainstream in more high-quality passenger vehicles.
I suspect that Siemens would have had even fewer orders, if Bombardier wasn't producing at capacity.
...and if
The 152 (and the Alstom Prima I) suffer from poor tracking at speed, resulting in excessive track forces, which is why they never received authorization in Austria, and why the Prima I only has limited approval in Germany and Switzerland.
(You find most of these in less detail in the diary.) *Lunatic*, n. One whose delusions are out of fashion.
Hm. If that's your source, I think Wikipedia errs in that. AFAIK 5.6MW is the new continuous rating, for which, as you say, a software change was enough, given that everything else came from a loco scaled for 6.4MW. I couldn't find a definite source (Bombardier says Dauerleistung = continuous power, but that may be a marketing 'mistake'), but in a forum where locomotive drivers debating just this subject, one posted this photo he made in a TRAXX 2 that ran in double, showing a higher temporary rating on a mountain climb ("Primärleistung" field):
*Lunatic*, n. One whose delusions are out of fashion.
Power is speed times force, so I'd think that doesn't tell much about grade climbing. Extra tractive effort on a slope is train mass x g x grade. So, ignoring force needed for acceleration and train resistance at standstill, for the Lötschberg mountain line maximum grade of 2.7%, 300kN would in theory be enough for 1130 tons (while 2x300kN would do it for 2260 tons). The locos are rated for 650 tons at that grade.
(Back to power, 5.6MW is enough to maintain 300kN up to a speed of 67.2 km/h.) *Lunatic*, n. One whose delusions are out of fashion.
The first is for the Vossloh Euro 4000 diesel -- as typical for six-axle heavy diesels, it shows a monotonous decline with speed, and the maximum power hyperbole (where TE ~= max power/speed) is reached very quickly:
Now here is the graph for the BLS Re 465, a four-axle high-power electric, under ideal conditions; with dashed curve for when the loco utilises only maximum continuous power, and the parallel solid curve for when it uses maximum one-hour power:
Under ideal weather conditions, before reaching the maximum power hyperbole, traction control limits TE to the rated maximum very strictly. (From actual measurements done on one new high-power loco by colleagues, I'd say precise to the kN.) *Lunatic*, n. One whose delusions are out of fashion.
Later in the same thread, I find this photo, too:
In the first line left is speed, right is target TE; the second line shows the target TE per bogie, the third line shows actual TE (from which power is just under 5.6MW); the next lines show target power in and out, then the actual metered electric powers, then the electric loss.
Unfortunately, the photographer doesn't say anything on continuous/one-hour, he just says the software menu of his locomotive [one of the first class 185 which was up-rated from 4.2 MW with the software change] said "5.6 MW". However, just found another locomotive driver in the thread claiming:
Having thought about it - I think lack of distinction should mean that maximum power is limited by temperature control only. That may or may not be fair to customers, depending on the level of heating: if full power is available in winter, but not in the summer, then the same trains can only be run slower in the summer -- and the differene is not guaranteed by the maker. This should not be an issue for the BLS and SBB locos, which utilise de-facto one-hour maximum power on climbs, but it may be an issue elsewhere.
It was planned to upgrade the earlier DB locomotives
See half-sentence in brackets in my previous comment: the earlier class 185 were upgraded, the photo shows one of them (but the class 145 wasn't AFAIK). *Lunatic*, n. One whose delusions are out of fashion.
(Weights: I have 84t vs. 82.5t, so it is even lighter - 320 kN giving 39.5% adhesion.) *Lunatic*, n. One whose delusions are out of fashion.
Wheel slip is just a notorious problem even with cleaning creep, sanding and cleaning brake blocks -- softwares are updated repeatedly, and they get national versions. *Lunatic*, n. One whose delusions are out of fashion.
