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The ALP-46 locomotives supplied to the US are like the German Br 101 locomotives, in that they use one Traction Converter per axle, while all European TRAXX locomotives use one Traction Converter per bogie.
by jfbeaulieu on Tue Jul 7th, 2009 at 01:49:34 AM EST
[ Parent ]
One final comment for tonight the change in rating for Bombardier TRAXX locomotives from 4200kW to 5600kW was a software change only, the change allows the higher output for One-Hour, while 4200kW remains the Continuous rating for the locomotive. The German Br 145 locomotives can receive this change if their owners so choose.
by jfbeaulieu on Tue Jul 7th, 2009 at 01:53:51 AM EST
[ Parent ]
4200kW remains the Continuous rating

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.

by DoDo on Tue Jul 7th, 2009 at 09:39:27 AM EST
[ Parent ]
Very interesting photograph, one tidbit of information not shown, would be of great interest to me, that is the Tractive Effort in kN. Power Consists (sets of locomotives coupled together) are limited on the Gotthard to a maximum of 600 kN, by the strength of the Drawgear. Anymore and you get into the safety margin, and might pull the train apart by breaking a coupling. I had been lead to believe that at above 5.6 MW the locomotive would produce more than 300 kN if the grade was steep enough to prevent the train from accelerating.
by jfbeaulieu on Tue Jul 7th, 2009 at 10:09:46 AM EST
[ Parent ]
From what I know, maximum tractive effort is a pretty strict limit software-side on the modern electrics, so it shouldn't go above.

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.

by DoDo on Tue Jul 7th, 2009 at 10:43:38 AM EST
[ Parent ]
Perhaps the two diagrams below will tell more about TE as function of speed than the above words.

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.

by DoDo on Wed Jul 8th, 2009 at 11:23:53 AM EST
[ Parent ]
Well for me the epiphany happened, the photograph shows  a figure of 6245kW for Primärleistung whereas the commonly quoted figure for TRAXX locomotives is 5600kW. The key to the difference is in the measurement location
Primärleistung is the input to the Primary Windings of the main transformer, while the 5600kW figure is "Leistung am Rad" at the Wheel, the difference is the losses due to heat and gearing. The difference is roughly 10% which is a commonly accepted figure.
by jfbeaulieu on Wed Jul 8th, 2009 at 01:19:19 PM EST
[ Parent ]
By jove, you're right! Though, methinks part of the 10% for asynchronous AC electrics are auxiliary units.

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:

Zumindest die privaten 185er haben 5,6 MW Dauerleistung. M.W. wird auch nicht mehr nach Stunden- und Dauerleistung unterschieden.At least the private [class] 185 have 5.6 MW continuous power. AFAIK there is no longer a distinction according to hourly and continuous power.


*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Wed Jul 8th, 2009 at 05:05:57 PM EST
[ Parent ]
Could very well be that the hourly and continuous ratings aren't meaningful anymore. I was told by an knowledgeable source that beginning with 185_051 for DB and 185_510 for the private operators all were built rated at 5.6 MW. This of course includes all Swiss owned locomotives. It was planned to upgrade the earlier DB locomotives, but perhaps this was never done. None of the earlier DB locomotives is homologated for Switzerland, but 30 are homologated for Austria.
by jfbeaulieu on Wed Jul 8th, 2009 at 09:55:45 PM EST
[ Parent ]
Could very well be that the hourly and continuous ratings aren't meaningful anymore.

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.

by DoDo on Thu Jul 9th, 2009 at 01:22:16 AM EST
[ Parent ]
Yep, no TRAXX with single axle control yet -- nor with 6.4MW and 200 km/h. It is interesting to note that in the lineage leading to the Baureihe 101, the switch from single bogie control to single axle control was between the SBB Re460 and the BLS Re465.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Tue Jul 7th, 2009 at 09:54:02 AM EST
[ Parent ]
Yes, the Re465s are more powerful than the Re460s.
by jfbeaulieu on Tue Jul 7th, 2009 at 10:14:04 AM EST
[ Parent ]
That increased power was mainly due to other improvements, but, under ideal weather conditions, the Re 465 also have more stable adhesion, resulting in a higher maximum tractive effort. (Power difference: 4.8 vs 6.27 MW continuous, 6.1 vs. 7MW one-hour rating; tractive effort: 300 vs. 320 kN.) Then again, that's ideal weather conditions -- I am not surprised to find that train weight limits are the same.

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Tue Jul 7th, 2009 at 11:08:28 AM EST
[ Parent ]
I don't have the weight for a Re465, but if it weighs 85 tonnes, then your wheelslip system needs to achieve a factor of adhesion of 38% to produce 320kN of pull, or 36% to produce 300kN. The later figure is reasonable, while the former is possible but has significantly larger risks, especially where delays caused by a stalled train cause cumulative delays to the whole system.
by jfbeaulieu on Tue Jul 7th, 2009 at 10:53:40 PM EST
[ Parent ]
Given that 38% can drop to 20% in rain (or when a snail climbs across the rails), I submit this whole maximum adhesion idea was moot.

(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.

by DoDo on Wed Jul 8th, 2009 at 08:35:11 AM EST
[ Parent ]
A drop from 38% to 20% solely due to rain is a terrible performance, and not indicative of a very sophisticated adhesion management system. Both EMD and GE for their modern diesels use a "Creep Control" system to achieve maximum adhesion whereby at speeds above 7 mph. wheel rotation is 7% faster than needed for the current ground speed, also the control computer will reduce power slightly to the leading axle to allow it to "Dress" the contact surface of the rail and eliminate material such as oil or squashed insects (caterpillars and locust are the worst) before the other axles pass. The much greater weight of North American diesels probably is high enough to break the surface tension of most materials likely to be found coating the rails which would help also.
by jfbeaulieu on Wed Jul 8th, 2009 at 01:36:07 PM EST
[ Parent ]
I didn't mean to include EMD in the part concerning lower power supplied to the lead axle, as since EMD lacks single axle control there is no way they could do that.
by jfbeaulieu on Wed Jul 8th, 2009 at 02:51:39 PM EST
[ Parent ]
"Dress" = cleaning creep (that's how I translate German Putzschlupf; I don't know if there is a British -> UIC English term) is a real benefit of single axle control - and an advantage of the 'rail-tearing' axle-hung motor Siemens EuroSprinters over the present Bombardier TRAXX locos. (There have been two major comparison tests I read of, one on the steep line to Blankenburg/Harz in Germany with its isolated 25kV/50Hz electrification, another on the Brenner route, with a DB 189 = ES64F4 coming out on top in both cases.) However, on four rather than six axles, that's still a 25% drop in adhesion. (Note that on the aforementioned Blankenburg line, the isolated electrification was dismantled in the end, and six-axle diesels took over.) Then there is sanding (and with that increased sand use and track/wheeltread wear), but that is not always stable, in particular for all four axles. There is also the cleaning brake block - which is not widespread enough across Europe for reasons that appear bureaucratic to me. And, as you say, axle weight is a third of the US, so it's all less stable. (Though still less bad for locos than for even lighter EMUs and DMUs.)

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.

by DoDo on Wed Jul 8th, 2009 at 04:18:08 PM EST
[ Parent ]

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