The Baldwin A1A-A1A 62073

Le 62073 en 2020

The 62073 at the depot of the CFTR in april 2022. (Picture Sébastien Kieffer)

General technical data of the locomotive:

Builder: Baldwin Locomotive Works, Philadelphia, Pennsylvania
Model/Type: DRS 6-4-660, N° 73188
Date of delivery: 5th of July 1947
Road numbers: 040DA73 than A1A-A1A 62073
Diesel Power [kW]: 560
Locomotive Power [kW]: 398
Max. starting tractive effort [kN]: 208
Max. safe speed [km/h]: 96 than 80
Weight in working order [t]: 109,5
Total length [m]: 17,72
On-board voltage [V]: 120

General characteristics of the prime mover:

Builder: Baldwin Locomotive Works, Philadelphia, Pennsylvania
Model/Type: De La Vergne type 600 NA
Cycle: 4 stroke
Air supply: Natural aspiration
Max. Power [kW] at engine speed [rpm]: 560 @ 625
Specific fuel consumption [g/kWh]: 233
Fuel consumption @ max.Power [l/h] 174
Max. Torquer [Nm]: 8550
Break Mean Eff. Pressure [bar]: 5,5
Linear piston speed [m/s]: 8,21
Number of cylinders [-]: 6 in line
Bore * Stroke [mm*mm]: 324*394
Displacement cylinder / total [l]: 32,48 / 194,9
Total mass of engine [kg]: 12644
Cooling method: water
Starting method: electric using the main generator
Système d'injection: 1 injector & 1 high pressure pump Bosch for each cylinder

Diesel prime mover builder plate:


General view:


Builder plate:


Short presentation:

This locomotive is certainly the most impressive of our collection. Its prime mover and its fantastic sound is the reason for the high interest for it among the railfans in France.

The 100 A1A-A1A 62000 (former 040DA) were built between april 1946 and august 1947 from the Baldwin Locomotive Works in Eddystone, in the suburb of Philadelphia in Pennsylvania and delivered to the french state railways SNCF, in the framework of the Lend/lease programm which goal was to rebuild Western Europe after WW2. The well known Mikado 141R were also part of this plan. For the Baldwin Builder, which was specialized since decades in the construction of steam locomotives in the USA (like ALCO and LIMA), this series is paradoxically its first large production experience for diesel locomotives. The precedent series for the domestic market were by far smaller.

First registered under the number 040DA (figure "4" for 4 drive axles, "D" for Diesel and "A" because these locomotives were the first diesel series in France) they were renamed "62000" in 1962 after the renumbering of the entire SNCF locomotives fleet.

These diesel-electric locomotives are equipped with a slow-running (max 625rpm), in-line 6 cylinder, 4-stroke, water cooled naturally aspirated Diesel engine from the 600-series. For each cylinder there is one cylinderhead equipped with 2 intake and 2 exhaust valves. These are controlled through a unique camshaft using two push rods and two levers. In the original engine called "VO", the combustion chamber was integrally built in the cylinderhead, a design which caused a lot of troubles that could not be corrected very soon because of the restrictions of the War Production Board (who prohibited design changes during WW2). The 600-series engine is a enhancement from the VO engine. One of the major change involves the combustion process. Therefore the cylinderhead has been completely redesigned and the VO flat top piston replaced by a Hesselmann-type piston with open combustion chamber principle. Fuel is now direct-injected in the combustion chamber using a Bosch high-pressure pump and one injector for each cylinder.

It is started by the prime generator which is shortly fed with current from the batteries. These were first lead batteries, then cadmium-nickel (for more than 40 years!) and now again lead-acid batteries (9 of 180Ah capacity).

The engine drives directly the prime generator, a double stage air-compressor from type "CD" (Westinghouse) and the propeller of the fan which cools down the water and oil radiators and the two blowers of the traction motors.  The exciter and auxiliary generators are driven by V-belts, like the ventilators for the traction motors are. All these equipments are delivered by Westinghouse.

Note that despite its (even for the US of the 40's) impressive dimensions, (displacement of 194L that's to say nearly 33L per cylinder), its engine is only rated at 750HP/492kW which is what the workshops of the SNCF have adjusted the injection pumps to. After all said auxiliaries, only 497kW are available for the prime generator.

 The engine belongs to the 600 series and is called 606NA because of its 6 cylinders and the Naturally Aspiration. The NA versions were rated from 660HP/492kW to 750HP/560kW. These engines were later turbocharged and called 606SC. They were rated  between 1000HP/746kW and 1325HP/988kW. The biggest versions of the 600 series were (and still are) the in-line 8 cylinders versions. Generally speaking, the number of 8 cylinders, naturally aspirated version is limited. These NA engines were rated at 1000HP/746kW but soon replaced by the 606SC with the same power output with 2 cylinders less. The 608 engine were later also supercharged and called 608SC. They could deliver between 1500HP/1119kW and 1750HP/1305kW power output.

The prime generator has a separate excitation. This excitation winding is fed by an exciter from which the excitation is composed of shunt (positive), a serial (negative) and a separate winding fed by the auxiliary generator. The current through this separated winding is limited by a system called "Carbonstat" (TS31) which purpose is to avoid the diesel engine to stall if the torque demand of the generator is too high. A modification done by the SNCF was to allow the locomotive engineer to vary directly this current by adding or subtracting resistors in this circuit. The driver can now choose the tractive effort at a given diesel engine speed.

The brake is an Westinghouse specialty: it is a kind of a triple valve. The GE has a similar system. It is a distributor 6 DKR which can be found as well on the 141R.

The chassis and the trucks are in cast steel. These trucks were first used on steamlocomotives or on their tenders and are equiped with 3 axles and 2 nose-suspended electrical traction motors from type Westinghouse 362 with 4 poles. The 14/68 gearing allows a maximum safe speed of 96km/h (60mph). Suspension uses leaf and helix springs and is fully equalized. The connection between chassis and trucks is also original.

These locomotives were the first experience of dieselization on a large scale for the french national railways, more through necessity then by choice. The reconstruction of France was at that time an absolute priority. Very soon, the trucks revealed to be very agressive for the track and the maximum safe speed has been limited to 80km/h (50mph). Also the journal boxes need continuously lubrication made by hand (Symington). This precluded early their use on long distance. So, they were more and more used only for yard works for example at humps, especially in the North (coal ore) and the Lorraine (iron ore). On both sides of the atlantic the Baldwin excelled on mining regions: Pennsylvania is the equivalent of the french Lorraine or the german Ruhr regions. They were very suited to the service on humps where the locomotive pushs long trains at a slow and regular speed with high tractive effort. The Westinghouse electric equipment was oversized (generator and traction motors were used on 1000HP locomotives) so that they could withstand high overloads without majour problems.

Electrical schematic view:

Schema Traction

Life at the CFTR:

Last owner before salvage: CFTPV
Retirement date: (SNCF) 1986 (Strasbourg)
Acquisition date: 2019 (CFTPV)
Current owner CFTR
Restoration: On-going
Utilisation: Will once run the train from depot to the station and switching at Sans-Soucis
Retirement by the CFTR: -

The 62073 (builder identification 73188 and not 73201 like shown above, which is the identification of the 62086) has been bought to the CFTPV in 2019 by our association, at the same time like the GE4032. It has been severely damaged by gypsies and needs hard restoration work, because a lot of parts have been stolen or damaged and made not usable anymore. The restoration will last at least 10 years...

Pictures at the CFTR: 

Baldwin 62073

Going out of the Tunnel in the suburb of Pontarlier in October 2021. (Picture Sébastien Kieffer)

Baldwin 62073

The 62073 arrived at our neighbor the Rhine Harbour: the parcel is received and needs a little bit more power: at least 2 locomotives. November 2021. (Picture Sébastien Kieffer)

Bibliography and external links:

  • Loco-revue documentary file;
  • SNCF characterstics file;
  • trains miniatures n°19, mai-juin 1988;
  • Voies Ferrées 78, juillet-août 1993;
  • Diesel Locomotives: the first 50 years. de Louis A. Marre, Kalmbach Books, 1995.
  • Train Shed Cyclopedia n°60, Newton K. Gregg, 1977. 
  • Diesels from Eddystone: the story of Baldwin diesel Locomotives , Dolzall, Kalmbach Books, 1984
  • Diesel Locomotives, Cyclopedia volume 2, compiled by Bob Hyden, Kalmbach Books, 1980.
  • La traction électrique et diesel-électrique, Pierre PATIN, collection des chemins de fer aux éditions Léon Eyrolles, 1952.
  • "The Baldwin Diesel Zone"
  • The Diesel Builders, Vol. 3,  Baldwin Locomotive Works, John F.  Kirkland, Interurban Press, 1994

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