RAILWAYANA
It might be informative to compare an SNCF ‘Pacific’ heavily loaded on a boat train between Amiens and Calais. Train services were less frequent in pre-TGV days in France and train formations were, on average, much longer and heavier than in Britain, with loads in excess of 550 tons common. After electrification between Paris and Amiens in May 1960, Calais-based ‘Pacifics’ only worked north of Amiens. Poppet-valve Class 231E Chapelon ‘Pacifics’ for the Nord Railway were retired in 1967, so services were in the hands of less powerful but perhaps more robust locomotives of PLM origin (Paris Lyon Mediterranée Railway), drafted in from 1950 following progressive electrification elsewhere. These PLM ‘Pacifics’ lasted until 1969. The run in Table 4 was made in September 1968 on Train 9, the 08.10 Paris-Nord to Calais Maritime.
Chapelon effect
Over 1,000 4-6-2s were built from 1907, mostly compounds, and the PLM had (by coincidence!) 462. Most were rebuilt in the 1930/40s to Chapelon principles, greatly increasing their power. PLM rebuilds kept piston valves and the double blastpipe and chimney design. Privatelyowned No. 231K8 still operates. In the Table 4 run, 231K 16 was tasked with 13 coaches and two four-wheel vans (585 tons tare, 650 gross), full and standing. Departure from Amiens was 3½mins late. After a ¾ mins PW slack at Dreuil, the ‘K’ whirled along the level in the low 70s. The speed limit was 120kph (74.6mph). The slight humps before Noyelles and Rang-du-Fliers cut the speed to 67-67½mph but ‘even time’ was achieved by Ponthoile (39.60 miles). A good climb was made of the 2½ miles at 1-in-133 to kilometre post 237.5 (Neufchâtel summit, minimum 47mph. We were now edging ahead of time, so did not exceed 64mph on the descent to Boulogne, reached 1 min early. Over the 50.7 level miles from Picquigny to Etaples we averaged 70.58mph. The load limit unassisted between Amiens and Boulogne was 700 tonnes (690 tons) but a pilot locomotive, either another ‘Pacific’ or, more likely, a US ‘141R’ 2-8-2, was normally required for loads of more than 500 tonnes on the 1-in-125 gradients between Boulogne and Calais, over Caffiers summit in both directions. On my run, however, no assistance was available so the ‘K’ had to take its 650-ton train unassisted and actually gained 2mins (net) on schedule. The start, up 1-in-125/167, was painfully slow but the ‘Pacific’ kept its composure, despite an adhesion weight of only 55 tons. Caffiers bank (six miles up at 1-in-125) is too long to be rushed, but speed only fell to 34mph at the top, good with such a heavy load. Signal checks into Calais cost 1½mins but arrival was punctual. Thanks to Alastair Wood, Conrad Natzio, Peter Rydall and George Carpenter for their assistance.