Display:
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 ]

Display:
Login
. Make a new account
. Reset password
Occasional Series