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He succeeded Edward Thompson as CME on 1 July 1946 but his style of work was more like Thompson's predecessor Sir Nigel Gresley. Peppercorn finished several projects which were started by Thompson, but most popular were his LNER Peppercorn Class A1 and the LNER Peppercorn Class A2.
Edward Thompson had set down a strict set of design guidelines for the incoming CME, relating directly to the upcoming design of Express Passenger Pacific Locomotive. The design was to draw heavily on the A1/1 Pacific Great Northern which had been rebuilt during Thompson's time in office. This would have created a cross between the A2/3 Pacifics, and Great Northern 's 6'8" driving wheels. By the time Peppercorn was in office, reports of Great Northern 's persistent frame problems, hot axleboxes, and steam leaks were all filtering back into the design office. The general belief was that the issue was being brought about because of a lack of frame support at the front end, largely due to the cylinders not being mounted aligned with each other (an aspect of divided drive combined with equal length connecting rods). Thompson's guidelines would have produced another locomotive with the cylinders apart, so Peppercorn decided against it, and brought the cylinders in line, and arranged the locomotive as something of a merging of both Gresley's A4 and Thompson's A2/1, creating first the A2 class, and then the A1.
Both of the Peppercorn Pacifics utilised a boiler incorporating a 50 sq ft grate, allowing for very high power levels to be produced, but at the cost of a relatively high fuel consumption, and consequently, though both the A1 and A2 classes were regarded as excellent locomotives, they were not especially popular with those who had to fire them. The A1s were intended to take over from the A4s on non-stop express duties, but they failed to dent the monopoly of the A4s over the London-Edinburgh Expresses, which after postwar frame alignment and fitting of double Kylchap Chimneys, became the standard bearer of the East Coast Main line once more.
The real strength of the A1 and A2 classes lay in their reliability. By carefully incorporating the best of Gresley and Thompson design, as well as ideas of his own, Peppercorn had produced two masterpieces of durability and low service cost. Some five of the A1's had roller bearings fitted throughout, and these five regularly clocked up mileages of over 150,000 between intermediate overhauls. Even the plain bearing A1's were capable of 90,000 miles between overhaul, and no other express passenger locomotive class in the UK could better 80,000. The first of his A2 engines has single chimneys, and when incorporated with a self cleaning smoke-box produced steaming problems which took some time to resolve. changing to Double Blast-pipe resolved much of the issues, though some of the A2's retained single chimney without self cleaning apparatus. The A1's, being built afterwards, and incorporating the lessons learned, featured the Double Blast-pipe and Chimney from new.
These were known as some of the best British steam locomotives ever in service, the A2's were particularly powerful, and finally produced the answer to the heavy services on the Edinburgh to Aberdeen Line which had blighted both Gresley (P2 Class- too long a rigid wheelbase) and Thompson (A2/2 and A2/3- both lacking adhesion). Upon Nationalisation and the foundation of British Railways, he continued in essentially the same job, now titled "Chief Mechanical Engineer, Eastern and North Eastern Regions"; he retired at the end of 1949, two years after nationalisation. Overall he was active as a railway Chief Mechanical Engineer for three and a half years.
However, a brand new A1, 60163 Tornado, built as the next in the class, has been constructed. It moved under its own steam for the first time in August 2008.
Arthur Peppercorn's widow was honorary president of the A1 Steam Locomotive Trust, builder of Tornado. At age 92, she lit the first fire in Tornado’s firebox in January 2008, and was later on the footplate for Tornado's inaugural steaming at Darlington works, stating "My husband would be proud.".
|Chief Mechanical Engineer of the
London and North Eastern Railway