Just for fun: where was this photo taken?

Grumpy Git

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I'm not one to take photographs of trains normally (or anything else for that matter), but armed with a new smartphone and happening by this very nicely prepared loco / train, I couldn't resist, (sorry its a bit shaky)?

Just for fun, can anyone say which country and what station
20191107_220015.jpg
 
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RailUK Forums

bspahh

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Sweden, but the station I’ve no idea.
I'll take a guess at Uppsala, as the trains to Narvik go through there, Stockholm central has a bigger canopy, lots of the smaller stations won't have a big canopy, and Uppsala one of the more likely places for someone from the UK to visit.
 

TRAX

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To be honest I think this can be quite a good game (if it gets harder than that), if people agree perhaps it can earn its place in the Quizzes & Games section ?
 

edwin_m

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Why does the loco have two pantographs?
Common practice in many Continental countries - I think it's just so there is a spare in case it goes wrong, although raising the rear one reduces the reflection of sparks into the driver's eyes. Some multi-voltage locos have different pantographs for different voltages, but I don't think this is one of them.
 

TRAX

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The first pantograph can also be used to scrape ice off the overhead contact wire, with the second used to actually draw current. This is certainly handy in northern countries.
And you are right, this is a single-voltage locomotive.
 

MarcVD

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Two pantographs are also quite useful when large amounts of current have to be drawn from the catenary. This is - or was, because with today's power electronics, it's less of an issue - particularly the case with 1500 or 3000 V D.C. electrification. Drawing 5000 amperes from one panto-catenary contact point is not a problem when the train is moving, but when starting, the heat generated at that point does not dissipate quickly enough and can easily melt the wires. So you will often see trains hauled by D.C. locs start with their two pantos up, and then one drop as soon as the train has gained enough speed. Not only freight trains, but also large passenger ones, which can easily draw up to 800 amps for just for hotel power.
 

edwin_m

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Two pantographs are also quite useful when large amounts of current have to be drawn from the catenary. This is - or was, because with today's power electronics, it's less of an issue - particularly the case with 1500 or 3000 V D.C. electrification. Drawing 5000 amperes from one panto-catenary contact point is not a problem when the train is moving, but when starting, the heat generated at that point does not dissipate quickly enough and can easily melt the wires. So you will often see trains hauled by D.C. locs start with their two pantos up, and then one drop as soon as the train has gained enough speed. Not only freight trains, but also large passenger ones, which can easily draw up to 800 amps for just for hotel power.
For completeness I should point out that Sweden has 15kV AC electrification, so that reason doesn't apply in this particular case.
 

edwin_m

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............ but it still reduces the current draw on each pantograph by 50%, (>240 amps at full load given the loco's 3.6mW output).
It does, but there's a big difference between 240 amps on the AC system and the 5000 amps quoted above for DC locos. Especially as, if the resistance of the pan-wire interface is the same, the amount of heat produced depends on the square of the current.
 

Grumpy Git

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That was one of the big advantages of using high voltage ac over 1,500v DC, the CSA of the copper on the OLE can be much smaller.

I think the bloke who decommissioned the Woodhead route is still living off the proceeds of the scrap copper!
 

MarcVD

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For completeness I should point out that Sweden has 15kV AC electrification, so that reason doesn't apply in this particular case.
Absolutely true. It is also a known fact that some AC locos, like for exampke the SNCF BB 15000, have been fitted with one panto only.
 

JonasB

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Sweden, but the station I’ve no idea.
Correct, I'm not sure how anyone can tell the station, I was being mischievous, but it was a sleeper and was heading due north.
It wasn't too hard to identify the station… :)

I'll take a guess at Uppsala, as the trains to Narvik go through there, Stockholm central has a bigger canopy, lots of the smaller stations won't have a big canopy, and Uppsala one of the more likely places for someone from the UK to visit.
Correct, track 2 to be specific.

To be honest I think this can be quite a good game (if it gets harder than that), if people agree perhaps it can earn its place in the Quizzes & Games section ?
On the biggest Swedish rail forum there is a weekly quiz with four images from an unknown location, run by the same person for over ten years now. Usually three images from Sweden and one from another part of the world. Anyone know where this image is taken e.g.? https://www.postvagnen.com/sjk-forum/showthread.php/11055-En-utländsk-tisdagsbild Quite fun actually.

Why does the loco have two pantographs?
Common practice in many Continental countries - I think it's just so there is a spare in case it goes wrong, although raising the rear one reduces the reflection of sparks into the driver's eyes. Some multi-voltage locos have different pantographs for different voltages, but I don't think this is one of them.
The first pantograph can also be used to scrape ice off the overhead contact wire, with the second used to actually draw current. This is certainly handy in northern countries.
And you are right, this is a single-voltage locomotive.
There are number of reasons. Redundancy is one, having a 2nd one is great if the first should fail. And for aerodynamic reasons it is better to have it in the rear end as it avoids the turbulence around the front at higher speeds. And if there is thick rime ice on the wire contact is reduced so using both improves the contact a lot.

For completeness I should point out that Sweden has 15kV AC electrification, so that reason doesn't apply in this particular case.
Not with this loco, but the Dm3s used both pantographs.

 

TRAX

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It wasn't too hard to identify the station… :)



Correct, track 2 to be specific.



On the biggest Swedish rail forum there is a weekly quiz with four images from an unknown location, run by the same person for over ten years now. Usually three images from Sweden and one from another part of the world. Anyone know where this image is taken e.g.? https://www.postvagnen.com/sjk-forum/showthread.php/11055-En-utländsk-tisdagsbild Quite fun actually.







There are number of reasons. Redundancy is one, having a 2nd one is great if the first should fail. And for aerodynamic reasons it is better to have it in the rear end as it avoids the turbulence around the front at higher speeds. And if there is thick rime ice on the wire contact is reduced so using both improves the contact a lot.



Not with this loco, but the Dm3s used both pantographs.

LKAB has always had mean machines !
 

MarcVD

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And the middle part supplied by?
Was almost sure tgat somrone would come with that question. Frankly, I have no idea. But Wikipedia tells that those locos indeed were originally double, with the third, cabless element added later.
 

JonasB

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Was almost sure tgat somrone would come with that question. Frankly, I have no idea. But Wikipedia tells that those locos indeed were originally double, with the third, cabless element added later.
Correct, but they have always been able to run with just one pantograph, there is a 15 kV cable on the roof that supplies power to all three parts. See image at: https://jvgfoto.se/fordon/ellok/dm3/dm3-1227-1243-1228/

And while they were built as more or less two independent locos permanently coupled to each other, the middle sections where dependent on the end sections and could not run on its own, not only due to the lack of pantograph. But renovations and rebuildings in the 70's and 90's have turned them into more or less one loco with some important equipment only being present in one of the thirds.
 

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