Paris-Lyon-Mediterrannee 4-8-0 Locomotives in France

Class 240P (Locobase 2581)

Second batch of rebuilds of an earlier de Glehn Pacific design by noted locomotive designer Andre Chapelon. Data from Thierry Stora's excellent French Compound Locomotives' Homepage ([] , later web address was [], last accessed 25 August 2019). Note that tractive effort as measured in France would work out as 45,771 lb in normal compound mode. The specifications table uses the 1924 ARA formula.

Tweaked a bit compared to the first twelve, these engines introduced mechanical stoking, roller bearings on the driving axles, forked coupling rods a la Union Pacific while changing cylinder volumes slightly. Thierry Stora helpfully organized the two intake and two exhaust valve diameters used in this design:

H.P. cylinders inlet valves diameter: 200mm (7.87").

H.P. cylinders exhaust valves diameter: 210 mm (8.26'')

L.P. cylinders inlet valves diameter: 265 mm (10.43'')

L.P. cylinders exhaust valves diameter: 275 mm (10.82)

They were heavily used in World War II, sometimes trailing as many as 28 passenger cars behind them. They could run up several miles of 0.8% grade with 787 tonnes and still crest the Blaisy-Bas at 59 mph. Chapelon's design offered nearly unbelievable economies. Coal consumption amounted to a meager 1.05 kg (2.3 lb) per HP/hour. And its horsepower topped out at 4,700.

Hollingsworth (1982) reports that they carried on until the electrification of the Paris-Lyon line in 1952 and that "proposals to use these engines elsewhere in France foundered, for reasons that were never adequately explained." As noted in our entry on the first twelve Chapelon 4-8-0s, the frame-wracking that such a prodigious increase in power must have imposed on the engine might, suggests OS Nock (RWC V, pl 181), explain their retirement.

Class 4 701 (Locobase 11453)

Data from Ernest Graham, "Express Passenger Locomotives; Paris, Lyons And Mediterranean Railway" The Railway Age Gazette, Vol XLVIII, No 1 (7January 1910), pp. 23-27. See also the PLM Wiki at [], last accessed 4 November 2011. Several builders supplied locomotives for this class:

Builder Years Road numbers

Batignolles 1907-1908 4 701-4 730, 4 781-4 815

1909-1910 4 863-4 887, 4 943-4 962

Creusot 1907-1908 4 751-4 780

PLM-Oullins 1907-1908 4 731-4 738

PLM-Arles 1907-1908 4 739-4 750

1909-1910 4 933-4 942

SFCM 1907-1908 4 816-4 850

1909-1910 4 888-4 912

Franco-Belge 1908-1909 4 851-4 862

1909-1910 4 913-4 932, 4 963-4 982

All Graham could say about these 12-wheelers was: "I understand these engines have been remarkably successful in service." Locobase is struck by the narrow Belpaire firebox that rode between the two rear axles, especially when compared with the rather large boiler. Other design features included a valve train that used a fixed 60% cutoff on the LP cylinders. The profile photo most often reproduced of this class clearly shows the doubled reverse rods that operated both sets of valve gear.

The latter 120 locomotives weighed in at 76,100 kg, the axle loading on each driven axle having risen 830 kg to 15,180 kg. The rest of the locomotive was essentially identical to the first 162.

Rated at 1,177 long tons at 36 km/h (22.4 mph), the class could be used for fast freight and for pulling passenger trains through the more difficult sections. Max speed was 85 km/h (52 mph).

Over 200 of the class was superheated from 1919 to 1931 with an installation that yielded 62.64 sq m (674 sq ft) of superheater area. By 1936, 213 of the engines had been so modified.