141-r and mountain railway lines

Auteur : Clive Lamming

Unlike roads, with gradients measured in centimetres per metre, railways, transporting loads in the hundreds of tonnes with a derisory expenditure of energy, only accept gradients measured in millimetres per metre. A 2,000-tonne train can be pulled at 100 km/h by a diesel locomotive with 2,000 bhp, or one horsepower per tonne! In contrast, a 40-tonne lorry requires 400 bhp, or 10 times as much energy.

Gradients represent a real challenge for railways. What's more, unlike diesel or petrol engines, the power of steam engines decreases as speed increases: it is therefore at its maximum when the train pulls away and then decreases rapidly if the train accelerates. This means that the possible towed load of 3,000 tonnes at 20 km/h is only 400 tonnes at 110 km/h. However, at the same speed, the towed load is divided by 3 or 4 if the train goes from a flat surface (no ramp) to a simple ramp of 10 mm per metre.

They were spared nothing... and as soon as they entered service, these brave 141-Rs found themselves on the dreaded mountain line known as the ‘Ligne des Alpes’, linking Grenoble to Marseille via the Croix-Haute pass and the Durance valley. Pictured here is an ‘R’ catching her breath at Clelles-Mens station, near the mountain pass.© IXO Collections SAS - Tous droits réservés. Crédits photo © Collection Trainsconsultant-Lamming

SNCF carriages known as ‘DEV AO’ (for Division des Études de Voitures et Acier Ordinaire) were, due to the fact that they were built in the immediate post-war period, pulled by innumerable 141-Rs for regional trains at, let's say, limited speed. Pictured here is a rare view of 141-R-1187 in 1975, taken by J.H. Renaud during an amateur outing.© IXO Collections SAS - Tous droits réservés. Crédits photo © Collection Trainsconsultant-Lamming

AN ACHIEVEMENT ON THE ALPINE ROUTE

Due to their limited speed, the 141-Rs may never have been praised for ‘beautiful strolls’ like those of the Pacific or Mountain, but their strength, especially in the mountains, led to some memorable achievements. During a busy departure for the Easter holidays in 1962, special train 11902 was towed on the Alpine route by BB diesel locomotives 66039 and 66040 departing from the Portes-lès-Valence depot, but on leaving the Gap station, not far from kilometre marker 264, the train ‘’crashed‘’ on a curve, unable to brave the 25-percent gradient to La Freissinouse.

Both diesel locomotives started with difficulty, the engines warming up, but the train failed to move. Appeal had to be made to ‘ auxiliaries up front’ and the only locomotive available was a single 141-R fuel locomotive, loaded and waiting at Veynes depot for a train to Marseille-Blancarde, its home depot. The locomotive arrived at the ‘scene’ at 11pm and was hitched to the head of the train, which consisted of two locomotives and 15 old PLM type OCEM coaches - a total of 875 tonnes! Without missing a single moment, the 141-R immediately set the train in motion. Its powerful banging exhaust echoed into the night, waking up the barrier guards and station chiefs.

The photographs, particularly of 141-Rs, by Lucien-Maurice Vilain are great classics, always carefully presented. Pictured here on the Bonson viaduct on the Alps line.© IXO Collections SAS - Tous droits réservés. Crédits photo © Collection Trainsconsultant-Lamming

OPERATION ON RAILWAY LINES WITH STEEP GRADIENTS

On the winding and hilly line along the Côte d'Azur, the 141-Rs pull the famous Mistral train, which weighs 300 to 400 tonnes depending on the day and composition, as well as other very heavy trains weighing up to 800 tonnes. The routes from Marseille to Toulon (67 km) or from Toulon to Saint-Raphaël (94 km) are covered in 44 and 61 minutes respectively, at a speed of barely 90 km/h, but only on stretches with very steep gradients of about 8 per thousand. Not even Pacific and Mountain could have done better than that.

THE R'S EXCLUDED ON THE MASSIF-CENTRAL, CAUSSES AND CEVENNES RAILWAY LINES

Hardly any ‘R’ locomotives are in use on these routes as there are many tunnels. The gauge of the R's is particularly generous and well-rounded, taking up the maximum available space, so the air in the tunnels circulates poorly around the engines and cabin temperatures can reach record levels! As a result, air circulation around the engines was poor and temperatures rose to unprecedented levels inside the passenger’s compartments As a result, the ‘R’ trains were more likely to be ‘slow’ south of Nevers, particularly on the Langeac line, known as the ‘line of a hundred tunnels’.

ELSEWHERE, AT THE SAME TIME

THE MOST BEAUTIFUL FRENCH LOCOMOTIVE

Locomotive 232 U 1 of the Hudson type operated in France from 1949 to 1960 on the Paris-Lille route. Railway enthusiasts still regard it as an aesthetic masterpiece, with its pure, aerodynamic lines.

To many railwaymen and enthusiasts around the world, the unique 232 U 1 was the most beautiful French steam locomotive. A masterpiece of the engineer Marc de Caso, built in 1949 at a time when steam locomotives were already irretrievably condemned, this machine heralded the new generation of modern steam locomotives. But it came too late, at a time when steam traction on the SNCF network was definitively being phased out and replaced by electric traction.

The splendid 232 U 1 in operation at Gare du Nord in the 1950s. Running alongside the Pacific Chapelon and the 241-P, both of which were no match for the performance of this model, the 232 U 1 was capable of withstanding the rigours of the La Chapelle depot workshops.© IXO Collections SAS - Tous droits réservés. Crédits photo © Collection Trainsconsultant-Lamming

HOW TO OUTPERFORM THE PACIFIC?

Built in 1948 by the Corpet-Louvet company in La Courneuve, it was equipped with almost all the improvements available at the time, plus needle and roller bearings throughout the mechanism. It was fitted with highly sophisticated equipment such as an automatic start system dosing steam into the high- and low-pressure cylinders, oil boxes and wedges automatically adjusting the play in the connecting rods, and so on. With a length of 15.7 m and a weight of 131 tonnes, it was capable of producing 2,000 kW (2,800 bhp) due to its fire grate with a surface of 5,175 m2. It headed fast trains of over 560 tonnes at 120 km/h, and was in regular use on the Paris-Lille service.

AN ERA

The 230-K-249, slightly streamlined for the occasion, was designated for the painful traction of the "train on tyres" that the SNCF tested in 1949-1950 on the Paris-Strasbourg line. Here the train is in the depot, as can be seen from the access stairs. The Bugatti trainsets did better in terms of speed.© IXO Collections SAS - Tous droits réservés. Crédits photo © Collection Trainsconsultant-Lamming