Paris-Orleans 4-8-0 Locomotives in France

Class 240.700 /240A (Locobase 9572)

Data from [], which reproduces the technical data presented in an exhibit at the French National Railway Museum at Mulhouse, and from "Continental Locomotives" as preserved in Mike's Railway History and the excellent French Compound Locomotives' Homepage ([] ).

Note that tractive effort as measured in France would work out as 45,639 lb in normal compound mode. The specifications table uses the 1924 ARA formula.

These were rebuilds of an earlier Pacific design by noted locomotive designer Andre Chapelon. They used the powerful PO 4500 class Pacifics but adopted a Belpaire firebox to fit in the narrower span between the last two sets of drivers. New features included cam-operated poppet valves actuated by Walschaert gear, Nicholson thermic syphons in the firebox, larger steam passages, and a KylChap double-exhaust.

The engines quickly proved their power, achieving 3,060 hp in tests at 120 kph (75 mph) and showed a sustained production of 2,800 hp at 65-129 kph (40-80 mph). And in a test run trailing 635 tons, the 4707 scaled the 0.75% (1 in 125) grade at speeds not less than 80 kph (51 mph); steam pressure remained pegged at 290 psi. And a flat run of 74.9 km (46 1/2 miles) averaged 128.3 kph (79.7 mph). even though the train had to slow to 105 kph (65 mph) while passing through Abbeville.

Later set of rebuilds can be seen in Locobase 1054.