SNCF Push Pull

RichmondCommu · 5 Jun 2011

G'day everyone,

During the late 80's/ 90's I spent many happy weeks inter railing in Europe and including of course the mighty SNCF! One thing that I used to notice was the large amount of non powered push pull stock and I have often wondered why this was? Surely it would have been more economical to have used EMU's or DMU's? To use an example I once saw a commuter train pull into Gare du Nord powered by what appeared to be nothing bigger than a large shunting locomotive and I’m pretty sure I saw people getting off it! Its top speed would have surely have been no more than say 30 mph and the acceleration must have been pitiful.

I've recently had summer holidays on the Cote d’Azur and local services are now powered by double deck EMU's so I assume this practice is being replicated across France?

I look forward to your replies!

Kind regards, Richmond Commuter!

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WestCoast · 5 Jun 2011

I haven't done a lot of travelling with SNCF, but I think their once numerous push-pull services have decreased considerably.

That seems to have been a trend throughout mainland Europe, however not so much on DB in Germany which I'm much more familiar with, being a regular traveller with them. Push-pull has not decreased at all: it's used on all InterCity/EuroCity services, plus the majority of the Regional Express services using double decker stock and some local services using older single deck stock.

talltim · 5 Jun 2011

Provided you have a standardised control system push pull is far more flexible than units. There's nothing to stop you using push pull with units as the propulsion either, providing they are powerful enough

PaulLothian · 6 Jun 2011

Cheaper to convert existing stock than to build new trains!

Gordon · 6 Jun 2011

I have always considered push pull to be more effective than unit. I have always believed that SNCF thought my way too because
• a loco is nice and heavy so a loco plus lightweight push pull set suffers fewer problems with adhesion in poor rail conditions
• a loco can be swapped if it fails, but the coaches remain usable

SNCF is going the 'Japanese/British' style with a massive conversion programme to regional units - much to the sadness of SNCF enthusiasts and European loco bashers.

However, at the moment there is still a decent amount of push pull with locos. Regional service are increasingly turning to new generation ‘plastic’ units, but you can still see 40 year old diesels and 30 – 50- year old electrics locos on push pull.

Quite a few of the remaining regional express services with long distance type corail stock are now push pull (eg in Rhone Alpes where the Dijon – Lyon – Grenoble, Lyon – Annecy etc services are Corail coaches plus older and some recently converted driving trailers.

As it happens I was in Rhone Alpes only 3 weeks ago specifically photting the 67300 push pulls, and in passing also photting and travelling the electric push pulls.

All can be seen in my album here:

http://gwizz.zenfolio.com/p417354679

Paris – Laroche and Dijon also use these push pull corails

The loco you thought was ‘just a large shunter’ was more than likely a BB8500, 16500, or BB17000, and they are more powerful than you might think – almost twice as powerful as a BR class 47 diesel…

These still work around Paris on double deck stock, and there are indeed 67 Alstom ‘Prima’ new generation electric locos in use so the practice of loco hauled push pull will be around for a fair few years yet!

.

Drsatan · 6 Jun 2011

PaulLothian said:
Cheaper to convert existing stock than to build new trains!

I think that approach was taken in Italy, when in the early 1990s FS decided to order new electric locomotives to haul push pull trains on regional services since their rolling stock fleet was in good condition. This approach was considered to be less expensive than ordering new multiple units.

If this approach was used in Britain, the majority of ex Cross Country and West Coast Mk2 and 3 coaches would have been formed into rakes of around five to 10 coaches long, hauled by ex WC 86s, 87s, and possibly surplus 47s and 67s on non electrified lines, used in push-pull formation. To me this seems like a far more efficient use of relatively new rolling stock than either scrapping or exporting.

Gordon · 6 Jun 2011

Drsatan said:
I think that approach was taken in Italy, when in the early 1990s FS decided to order new electric locomotives to haul push pull trains on regional services since their rolling stock fleet was in good condition. This approach was considered to be less expensive than ordering new multiple units.

If this approach was used in Britain, the majority of ex Cross Country and West Coast Mk2 and 3 coaches would have been formed into rakes of around five to 10 coaches long, hauled by ex WC 86s, 87s, and possibly surplus 47s and 67s on non electrified lines, used in push-pull formation. To me this seems like a far more efficient use of relatively new rolling stock than either scrapping or exporting.

Absolutely, and then when the locos life expire you can use new ones which benefit from the latest technology, exaclty as with the SNCF 27300s.

However, I think the accountants will usually win the argument and say that a batch of lightweight 'plastic' EMUs is chepaer than a batch of modern locomotives.

Drsatan · 6 Jun 2011

Gordon said:
Absolutely, and then when the locos life expire you can use new ones which benefit from the latest technology, exaclty as with the SNCF 27300s.

However, I think the accountants will usually win the argument and say that a batch of lightweight 'plastic' EMUs is chepaer than a batch of modern locomotives.

Besides the perverse system used in the UK means that the leasing charges per annum for a 30 year old Mk2 coach are dispraportionately high due to its age. Factor in that if a TOC wants to operate loco hauled trains, it has to lease locomotives, traincrew and rolling stock, which makes operating locomotive hauled trains prohibitively expensive compared to operating multiple units. If the leasing and track access charges system didn't mitigate against the use of loco hauled trains I think they would be more common.

Locomotive hauled trains are also seen as 'old-fashioned' whereas multiple units are 'new and exciting'. However, the Mk2s currently used by New Zealand railways (http://en.wikipedia.org/wiki/NZR_British_Rail_Mark_2_carriage) look brand new because they've been extensively refurbished.

RichmondCommu · 6 Jun 2011

Gordon said:
I have always considered push pull to be more effective than unit. I have always believed that SNCF thought my way too because
a loco is nice and heavy so a loco plus lightweight push pull set suffers fewer problems with adhesion in poor rail conditions
a loco can be swapped if it fails, but the coaches remain usable

SNCF is going the 'Japanese/British' style with a massive conversion programme to regional units - much to the sadness of SNCF enthusiasts and European loco bashers.

However, at the moment there is still a decent amount of push pull with locos. Regional service are increasingly turning to new generation plastic units, but you can still see 40 year old diesels and 30 50- year old electrics locos on push pull.

Quite a few of the remaining regional express services with long distance type corail stock are now push pull (eg in Rhone Alpes where the Dijon Lyon Grenoble, Lyon Annecy etc services are Corail coaches plus older and some recently converted driving trailers.

As it happens I was in Rhone Alpes only 3 weeks ago specifically photting the 67300 push pulls, and in passing also photting and travelling the electric push pulls.

All can be seen in my album here:

http://gwizz.zenfolio.com/p417354679

Paris Laroche and Dijon also use these push pull corails

The loco you thought was just a large shunter was more than likely a BB8500, 16500, or BB17000, and they are more powerful than you might think almost twice as powerful as a BR class 47 diesel

These still work around Paris on double deck stock, and there are indeed 67 Alstom Prima new generation electric locos in use so the practice of loco hauled push pull will be around for a fair few years yet!

.

Thanks for this, very interesting stuff! I've always thought that an EMU / DMU would accelerate much more quickly than loco hauled push pull stock making them preferable for commuter services.

I've looked up the loco classes that you mentioned and certainly remember the BB8500 working push pull services on the Côte d'Azur and they certainly seemed to be pretty quick off the mark. However, the loco that we saw pulling into Gare du Nord was definitely a diesel with a centre cab (hence me calling it a large shunter). Now it might have been ECS but it was early in the morning, i'm sure we saw passengers disembark and surely an ECS push pull service would be hauled by the loco due to operate the train?

Peter Mugridge · 6 Jun 2011

Sounds like one of these?

http://www.google.co.uk/search?q=sncf+bb63000&tbo=p&tbm=vid&source=vgc&hl=en&aq=f

RichmondCommu · 7 Jun 2011

Peter Mugridge said:
Sounds like one of these?

http://www.google.co.uk/search?q=sncf+bb63000&tbo=p&tbm=vid&source=vgc&hl=en&aq=f

Yes Peter, just like one of those! Which is why i found it so odd and which is why it has stuck in my mind all these years (since the late 80's!).

Peter Mugridge · 7 Jun 2011

Well, the BB63xxx have a maximum speed of 90 km/h ( roughly 56mph ) so I would also be surprised if, even in those days, one was on a passenger service out of a busy terminal like Paris Nord.

Unfortunately I didn't start bashing in Paris until the 1990s, so we need someone with a longer knowledge of the area's services to answer this further.

RichmondCommu · 7 Jun 2011

Peter Mugridge said:
Well, the BB63xxx have a maximum speed of 90 km/h ( roughly 56mph ) so I would also be surprised if, even in those days, one was on a passenger service out of a busy terminal like Paris Nord.

Unfortunately I didn't start bashing in Paris until the 1990s, so we need someone with a longer knowledge of the area's services to answer this further.

Ok thanks Peter. I would not be terribly impressed if one of those took me into Waterloo on my morning commute! At that time there were also gas turbine units operating out of Gare du Nord too and they were damn noisy! I also recall ancient looking DMU's at Amiens. I also recall catching Le Train Bleu from Calais. Good times!

Gordon · 7 Jun 2011

RichmondCommu said:
I've always thought that an EMU / DMU would accelerate much more quickly than loco hauled push pull stock.

I've looked up the loco classes that you mentioned and certainly remember the BB8500 working push pull services on the Côte d'Azur and they certainly seemed to be pretty quick off the mark.

However, the loco that we saw pulling into Gare du Nord was definitely a diesel with a centre cab but it was early in the morning, I’m sure we saw passengers disembark and surely an ECS push pull service would be hauled by the loco due to operate the train?

answers to three points in order are:
Certain combinations of loco and push pull are just as quick to accelerate as a unit. Certainly SNCF lightweight push pull sets such as RIO and RRR are very lightweight and a three car set with a 67300 or 400 diesel accelerates pretty quickly (having recently witnessed this). Heavyweight inter city push pull sets might be a bit slower off the mark, but not much. Certainly Swiss push pull loco hauleds are also pretty sprightly (even huge long rakes of double deckers) as the electric locos used are so powerful.

On the Cote d'Azur it would not have been a BB8500 (dc only) but rather a 25500 (bicurrent dc and ac) All traction on the Cote D'Azur is bi current because Paris - Marseille was electrified at 1500v DC, but Marseille - Ventimiglia came later so was wired at 25kv ac. A few 25500 push pulls are left in the area but loads of new plastic have infiltrated.

As you say it was early morning, I suspect it was one of the later uses of 63500 on passenger, and that was to haul the occasional through night trains round the Paris ‘ceinture’ ring line. Certain trains with through sleepers and couchettes such as Calais Maritime - Venice used to do this. I travelled thus from Paris Nord to Paris Lyon in about 1978 behind 63858.

The 63000/63500 diesels were used on local passenger trains in the early days (late 1950s – 1960s but not on Paris commuters IMHO. An exception which lasted into the 1980s was the use of 63500s on the rush hour hauled trains on Charleville – Givet in the Ardennes.

.

TGV · 7 Jun 2011

Loco push pull may accelerate as quickly as *some* multiple units in dry conditions, but when railhead conditions are poor, despite the extra adhesive weight, I'd want 16 or 32 driven wheels instead of 8.

I have worked with locos that struggle with 12 driven wheels because the rail is wet, and it's on an uphill curve. EMU's on the same stretch have no problem despite having an axle load at the driven wheels of 4t less than the loco. Overall train weight is identical (indeed, it was a loco PULLING a dead EMU).
--- old post above --- --- new post below ---
EDIT: All vehicles were SNCF.

Gordon · 10 Jun 2011

TGV said:
despite the extra adhesive weight, I'd want 16 or 32 driven wheels instead of 8.
.

Take your point , however in my mind I was comparing a French heavyweight 4-driven-axles loco with a 'traditional' British EMU such as a 319 (my daily transport on Thameslink) which has (doesn't it?) a lightweight power car with only 4 driven axles trying to shift four coaches

TGV · 10 Jun 2011

Yes indeed Gordon - very good point. Some multiple units like the UK 317/8, 321, etc... have only 4 driven axles. Having 8 for an 8 car formation is an improvement on a 4 or 6 axle loco pulling the same equivalent weight.

I've often had people quote me theoretical tractive effort figures, but in my experience when the rail is wet, the track is not even (track twist) and there is gradient involved, I'd put away the books and see what happens for real! Pirelli's old adverts said it best: "Power is nothing without control"!

SNCF Push Pull

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