L'heure bleue: a new French layout

[Andy Hayter]

Excellent.  As a comment but not a criticism, locos would typically (but by no means universally) run with the rear rather than the front pantograph in use.   Discussions on the whys and wherefores have not afaik defined exactly why, but the most likely reason is that if there is any arcing between the pantograph and the catenary using the rear pantograph means the driver is not momentarily blinded or distracted. 

 

Of course dual voltage locos may not afford that luxury.  

 

This is more critical with the early AC locos in the 12xxx, 13xxx and 14xxx series where the pantograph is in front of the driving position.

[St Enodoc]

6 hours ago, Pacific231G said:

That makes perfect sense Barry. While delving a bit I found this  https://www.globalrailwayreview.com/article/93111/an-alternative-overhead-system-the-rigid-overhead-conductor-rail-system/

Furrer+Frey seemed to be presenting this as a new idea but I'm sure it's been used for ages. under the canopy seems very logical and one of the suggested uses for ROCS. I also found this from Indian Railways

https://rdso.indianrailways.gov.in/uploads/files/TI_IN 0041.pdf

Been done in depots for donkeys' years, usually hinged to swing out of the way to allow roof access. I think others have done it for main line use but perhaps F&F have some sort of unique selling point. Perhaps a real electrification engineer will tell us.

[Gordonwis]

21 hours ago, St Enodoc said:

Been done in depots for donkeys' years, usually hinged to swing out of the way to allow roof access. I think others have done it for main line use but perhaps F&F have some sort of unique selling point. Perhaps a real electrification engineer will tell us.

 

Rigid rail for main line use was developed in a big way in the early 1990s for use in Alpine tunnels (hence Swiss company F+F being the driving force). I remember noticing some on the Paris RER during a family trip to Paris in 2007 - I have found the location on street view :

 

https://goo.gl/maps/aYu3DyAeKDMuXrjH8

 

 

 

[Gordonwis]

On 14/07/2023 at 21:14, Andy Hayter said:

Excellent.  As a comment but not a criticism, locos would typically (but by no means universally) run with the rear rather than the front pantograph in use.   Discussions on the whys and wherefores have not afaik defined exactly why, but the most likely reason is that if there is any arcing between the pantograph and the catenary using the rear pantograph means the driver is not momentarily blinded or distracted. 

 

 

 

There are definite rules governing pantograph use. Every so often some or all of these are covered in articles in French railway magazines. The best known 'rule' is perhaps the one that requires the forward pantograph to be used if a loco is pulling a train of new cars wagons (to prevent spark damage to the road vehicles)

 

Don't forget that SNCF locos often start off (especially if pulling a heavy train) with both pantos up and that  'dual voltage' SNCF' locos can run with both pantos up at slow speed even if one is ostensibly for 'the wrong voltage' 

 

 

 

 

[Pacific231G]

10 hours ago, Gordonwis said:

 

 

There are definite rules governing pantograph use. Every so often some or all of these are covered in articles in French railway magazines. The best known 'rule' is perhaps the one that requires the forward pantograph to be used if a loco is pulling a train of new cars wagons (to prevent spark damage to the road vehicles)

 

Don't forget that SNCF locos often start off (especially if pulling a heavy train) with both pantos up and that  'dual voltage' SNCF' locos can run with both pantos up at slow speed even if one is ostensibly for 'the wrong voltage' 

 

 

 

 

Very interesting Gordon. I wasn't aware that SNCF's dual voltage locos had separate pans for each system and AFAIK the dual-voltage TGVs only have one for each power car.

I'm rather intigued by the quad voltage CC40100, originally designed for international TEE services,  that had four pans- one for each system - and have never really undestood why they were designed that way rather than having the switching between the different systems downstream of the actual pans.

It is true that lower voltage systems (1500Vdc for SNCF)have to handle higher currents for the same power while conversely higher voltage systems (25kV50Hz for SNCF)  need larger air gaps to avoid arcing but are there designs differwences between the pans themselves (on the CC40100s they don't look any different) ? 

Where such differences are not an issue I'd always understood that the reason for preferring to use the rear pan was that if the loco encountered a damaged section of overhead line the pan in use might suffer damage but if the front pan was down it probably wouldn't so making repair a lot cheaper.

Edited July 16, 2023 by Pacific231G

[Barry Ten]

Thanks for this stuff about pantographs; it's interesting. I hadn't really given it any consideration, although I've tested my locos in both directions with a given pantograph just in case there's a tendency to snag in one direction and not the other. For practical reasons, I won't be raising or lowering them during operations though, so they may be "wrong" 50% of the time. At the moment I'm counting it as a win if I can get close to reliable operation with them up in the first place.

[Barry Ten]

On 14/07/2023 at 20:07, Pacific231G said:

 

It looks very good Barry (though why did you film it in portrait rather than landscape?).

 

 

 

I'm new to smartphones I'm afraid, so still making idiot mistakes! 😆

[Gordonwis]

On 17/07/2023 at 13:09, Barry Ten said:

Thanks for this stuff about pantographs; it's interesting. I hadn't really given it any consideration, although I've tested my locos in both directions with a given pantograph just in case there's a tendency to snag in one direction and not the other. For practical reasons, I won't be raising or lowering them during operations though, so they may be "wrong" 50% of the time. At the moment I'm counting it as a win if I can get close to reliable operation with them up in the first place.

 

 

In contributing to another forum I needed to dig this picture out of my files. 

 

A somewhat lucky shot of two regional expresses passing at Beaune in June 2022 on my 'all loco hauled' trip Paris - Dijon (overnight)  - Lyon - Geneve  (I had stopped off for an hour in the hope of some freight 'filling the gap' (which it did)); the right hand train is the next southbound that I was waiting for to go to Lyon.

 

This is a great example of both 'ac' and 'dc' pantographs being raised under pure 1950s 1500v dc catenary (also illustrates well the fact that both pantos face the same way on the dual system BB22200 class

 

 

Edited July 27, 2023 by Gordonwis

[Barry Ten]

A lot of complicated catenary going on there which I don't understand ... the middle bit is of different design to the outer pair, for instance, without the separate contact wire(s).

[Pacific231G]

On 17/07/2023 at 13:31, Barry Ten said:

 

I'm new to smartphones I'm afraid, so still making idiot mistakes! 😆

Don't worry Barry, a glance at UGC- user (i.e. public) generated content- on the TV news after any disaster shows how that seems to be the natural way to hold a smartphone (designed for selfies I assume) and apparently TikTok  demands its video content to be shot in portrait.

You can actually get broadcast quality video with a smartphone and the basic tricks are

1. shoot in landscape mode,

2. keep the camera/phone steady and still for at least ten seconds at a time: don't wave the camera/phone around trying to see everything (in a riot say) as you'll wind up with no usable shots at all

3 Don't zoom within a shot but treat any use of the zoom as a new shot. 

4 If you want to interview someone or talk to camera, hold or place the microphone in the earbuds close to the speaker's mouth  rather thanrelying on the internal microphone. 

5 Selfie sticks can be used as monopods or to steady the camera and you can get phone mounts quite cheaply that screw onto tripods.

Edited July 28, 2023 by Pacific231G

[Gordonwis]

14 hours ago, Barry Ten said:

A lot of complicated catenary going on there which I don't understand ... the middle bit is of different design to the outer pair, for instance, without the separate contact wire(s).

 

There's a simple explanation for that, the middle road presumably has a lower speed limit as it is not the main running line. French 1500v dc overhead, like older British overhead, had a third wire (known as 'compound' catenary, as in those days it was deemed necessary for robustness  but it was not required in yards and on sidings where speeds were low. As technology moved on it was found that simple overhead with just two wires worked just fine in most applications. Indeed SNCF later discovered that a single wire (dubbed 'fil trolley' as it was like a simple urban tramway wire) could be used even on some 'main line'  sections (eg Bellegarde - Evian)

Edited July 28, 2023 by Gordonwis