European Railroad Discussion > End of an era, SNCF CC72000 diesel electrics

Recently, the French national railway, SNCF withdrew the last CC72000 diesel electrics. A couple survive in preservation, including one at the National railway museum at Mulhouse.

The 92 CC72000's were built by ALSTHOM's Belfort shops between 1967 and 1974. They were powered by a V-16 AGO prime mover developing 3350 horsepower (in North American terms 3000 hp). The prototype had twin 1500 h.p. Pielstick prime movers, however the production locomotives had a single prime mover.

In common with many other French diesels and electrics, they featured "monomoteur" technology, meaning a single traction motor per truck.

They featured the "nez casse" (broken nose) cab design common to many French locomotives of the 1970's.

Electrification and the creation of high speed rail lines saw them relegated to secondary duties, with many going to the SNCF "Fret" (freight) subsidiary.

With their original prime movers, they were loud and very smoky. Switzerland banned them with the original prime movers.

In the early 2000's,they were re-engined with Pielstick V-16's, which solved the smoke problem but they remained loud and proud.

Jouef and Roco made HO models of the CC72000's

My image shows SNCF CC72080 at Paris Gare de L'Est in 1995.



Edited 1 time(s). Last edit at 11/12/17 08:47 by eminence_grise.

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How does the "monomoteur" technology work? Are these locomotives 4-axle or 6-axle, and how many produced traction?

They are C-C's. The axles are all powered and are connected to the traction motor (one per truck) by drive shafts.

Amtrak tested an SNCF electric locomotive, but the "monomoteur" drive system scared them off and they went for the more conventional Swedish design.

eminence_grise Wrote:
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> They are C-C's. The axles are all powered and are
> connected to the traction motor (one per truck) by
> drive shafts.
>
> Amtrak tested an SNCF electric locomotive, but the
> "monomoteur" drive system scared them off and they
> went for the more conventional Swedish design.

Monomoteur drive sounds like it could work on a Diesel-Hydraulic locomotive too.

PHall Wrote:
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.
>
> Monomoteur drive sounds like it could work on a
> Diesel-Hydraulic locomotive too.

The traction motor was large and body mounted, with complex and flexible drive shafts connecting the motor to the trucks.

PHall Wrote:
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>
> Monomoteur drive sounds like it could work on a
> Diesel-Hydraulic locomotive too.


I am no engineer, but I always thought that hydraulic drives were effectively the same thing as a monomotor. However I seriously don't really understand quite how hydraulic drives are constructed so I might be completely wrong!

A good few years ago (before the TGV EST opened) I deliberately chose to head to Switzerland via the line through Belfort. On the way back we seemed to lose about 30 mins at Mulhouse as either the engine failed or there were problems completing the coupling - some trains changed from electric to diesel there. We managed to catch up all of the time by the time we got to Paris, which either shows that the timetable was very slack or the driver was pushing it. I suspect a bit of both.

Thanks very much for this perfect image, I didn't know that these locos had finally been withdrawn, which seems like a great tragedy (unless you had to live and work in the neighbourhood near their operation).

We visited Morocco some years ago, which is very interesting not least for the overwhelmingly French quality of the railway system. Much of their equipment has been either made in France, or purchased second-hand from there.

I believe that identical locomotives were delivered new in the early 1970s, and have recently been supplemented by some purchased from France as being surplus to their requirements.

Picture 1 shows one on a passenger working, while Pic 2 is of a second hand French loco placed in service without repainting. It is still in its SNCF Fret livery.

These photos were all taken at Fez, before we boarded the train to Marrakesh. A wonderful trip, I would highly recommend it.

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Some of the Moroccan locomotives were built new by ALSTHOM, and are identical to the SNCF CC72000's

eminence_grise Wrote:
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> Some of the Moroccan locomotives were built new by
> ALSTHOM, and are identical to the SNCF CC72000's


Thanks, as I thought!

ALSTHOM, now shortened to ALSTOM, stood for Alsatian Thompson Houston, a pioneer diesel engine manufacturer. There was also BTH, which stood for British Thompson Houston.

eminence_grise Wrote:
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> ALSTHOM, now shortened to ALSTOM, stood for
> Alsatian Thompson Houston, a pioneer diesel engine
> manufacturer. There was also BTH, which stood for
> British Thompson Houston.

No "p" in Thomson, and the whole name was rendered in French, of course.

These, and their electric brethren, always reminded me of same-period Winnebagos.

Regarding the comment about hydraulic drives, it's basically somewhat like your car or truck. The diesel motor is connected to a transmission, which is usually located in the center of the locomotive in about the same area as the fuel tank on diesel electrics. From there, a drive shaft extends out both ends into the trucks.

eminence_grise Wrote:
-------------------------------------------------------
> They are C-C's. The axles are all powered and are
> connected to the traction motor (one per truck) by
> drive shafts.
>
> Amtrak tested an SNCF electric locomotive, but the
> "monomoteur" drive system scared them off and they
> went for the more conventional Swedish design.


I also believe their ride quality and tracking was bad. Supposedly the French railroad tracks were smoother and better maintained in the late 1970's than Penn Central / Conrail / Amtrak's. Whodathunkit.

Brian

choodude Wrote:
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> eminence_grise Wrote:
> --------------------------------------------------
> -----
> > They are C-C's. The axles are all powered and
> are
> > connected to the traction motor (one per truck)
> by
> > drive shafts.
> >
> > Amtrak tested an SNCF electric locomotive, but
> the
> > "monomoteur" drive system scared them off and
> they
> > went for the more conventional Swedish design.
>
>
> I also believe their ride quality and tracking was
> bad. Supposedly the French railroad tracks were
> smoother and better maintained in the late 1970's
> than Penn Central / Conrail / Amtrak's.
> Whodathunkit.
>
> Brian

As I heard it at the time (from some of my co-workers who were closer to Amtrak than I was, and from a couple of Amtrak people I knew), the ride was not too good on the main lines, but this they could live with; the real problem was on yard tracks, where the very rigid, short-wheelbase C-C trucks were constantly derailing. Also, this locomotive was longer and heavier than what Amtrak wanted. Originally, according to several sources, Amtrak liked, and wanted to test, a Swiss Re 4/4; but SBB and the builder were on a very tight delivery schedule, and SBB simply would not agree to let Amtrak borrow one for a year. Since they could not get the Swiss loco, Amtrak chose the closest alternative available at that time, which was the Swedish ASEA Rc4; SJ (Swedish RR) was willing to wait an extra year for one of their new units, and so Amtrak 900 [or was it 990?] lived in the US for a year, and Amtrak liked it. I heard from several people that the only reason the French locomotive was brought over was that some French companies with strong connections in the US pitched such a "hissy fit" at not being considered, that Amtrak was pretty much forced into testing their locomotive, even though it did not come near to meeting Amtrak's requirements (all expenses were supposedly covered by the French companies involved, not by Amtrak).

Another thing I'm not sure about: I know that the first version of the "monomotor" trucks had a single truck-mounted (not body-mounted, as eminencegris said) traction motor, driving the axles through a gear train mounted outside the wheels and truck frame, but enclosed in a protective casing. It was my understanding (but I could be wrong) that the later monomotor trucks used a similar gear train mounted between the frames, not driveshafts as mentioned by eminencegrise. I would really like to know which drive train was actually used; can any TO experts step up and tell us? Thanks!

Roger Lewis (airbrakegeezer)

airbrakegeezer Wrote:
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> Another thing I'm not sure about: I know that the
> first version of the "monomotor" trucks had a
> single truck-mounted (not body-mounted, as
> eminencegris said) traction motor, driving the
> axles through a gear train mounted outside the
> wheels and truck frame, but enclosed in a
> protective casing. It was my understanding (but I
> could be wrong) that the later monomotor trucks
> used a similar gear train mounted between the
> frames, not driveshafts as mentioned by
> eminencegrise. I would really like to know which
> drive train was actually used; can any TO experts
> step up and tell us? Thanks!
>
> Roger Lewis (airbrakegeezer)

Yes, later versions used inside mounted geartrain. Also the monomotor bogies could shift gears when stationary between a freight gearing with 85 kph. maximum speed and a 160 kph. when the passenger gearing was selected.

SOO6617 Wrote:
>
> Yes, later versions used inside mounted geartrain.
> Also the monomotor bogies could shift gears when
> stationary between a freight gearing with 85 kph.
> maximum speed and a 160 kph. when the passenger
> gearing was selected.

Thanks, SOO6617! I had a feeling that you would know. I had forgotten about the gearshift arrangement -- old age and all that. Thanks again for reminding me.

Roger Lewis (airbrakegeezer)

Incredible, the locomotive in this photo shrunk and is in a box in my house! Oh wait! I have an HO Jouef model with exactly the same number as in the photo. It drives members of my model railroad group crazy when this French locomotive turns up in the middle of their US trains!

Thanks for posting and everyone for a nice discussion.

DaleR