1934 LNER ‘A1’ 4-6-2 No. 4472 Flying Scotsman
Between 1935 and 1939, the LNER set standards of scheduled high-speed steam operation that were never equalled in the UK. Those speeds were not on a par with those achieved in the USA by the ‘Atlantics’ and ‘Hudsons’, or the ‘Hiawathas’ during the same years, but there is a lot of similarity in the origins of both. One was the use of a less powerful and non-streamlined steam locomotive to test the feasibility of operating daily highspeed passenger train services. So the run by Flying Scotsman on November 30 1934 mirrored the Milwaukee Road’s trial in the same year. Both trains ran faster than any other steam locomotive had ever run before over long distances in their respective continents, and both reached a maximum speed that made them candidates for the title of the first steam locomotive to run at 100mph. Indeed, for many years before I started my research into this subject, I was convinced that the claimed ‘ton’ by No. 4472 was the first fully documented 100mph by a steam locomotive. But was it?
With just a four-coach train and with famed driver William Sparshatt at the controls, the Gresley ‘Pacific’ ran the 185.8 miles from King’s Cross to Leeds in 151 minutes and 6 seconds. The load was increased to six coaches for the return, and it was on the descent of Stoke Bank, between Little Bytham and Essendine, that the dynamometer car recorded a momentary 100mph. That claim remained largely undisturbed, (although not by O.S. Nock in his book Speed Records on Britain’s Railways), until a 2003 Steam Railway article (SR286), published evidence that to me, and other exponents of timing locomotive performance, completely undermined the claim. Two key facts emerge from the article. Referring to the timings of C.J. Allen, who was on board with his stopwatch that day, O.S. Nock says: “C.J. Allen clocked two alternative quartermile speeds of 97.3mph, whereas the dynamometer car chart showed a marked but rather unnatural peak of exactly 100mph. Allen himself… quoted 98mph in his log.” The second fact was the reproduction in Steam Railway of the dynamometer car chart over the stretch where the claimed 100mph was reached. This shows a steady and slow build-up of speed through the 90s, as one would expect. Then there is a sudden jump in the chart to 100mph and a jump back down again to a speed in the 90s, as if the recording pen had been jolted. Indeed, it must have been moved by a force other than the speed of the train because the sudden acceleration indicated by the chart would be impossible. Putting the sight of that reproduced chart and the comments of the timings together leaves no doubt in my mind that No. 4472 reached 98mph as a maximum. Even though the above invalidates the claim, I have taken the matter further by modelling the descent between Little Bytham and Essendine, where the ‘ton’ was claimed, on a computer spreadsheet. Taking into account the grades, I have assumed the maximum would have occurred just south of Little Bytham, which was passed at 95.5mph. The 1-in-200 downhill grade ends just south of the village, where the dynamometer car chart shows the claimed 100mph. It is unrealistic to assume the ‘A1’ could have accelerated up to 100mph on the subsequent easier grades, including some level and some slightly uphill track. From my calculations, it is likely that to have attained 100mph, No. 4472 would have had to travel between Little Bytham and Essendine nearly 2 seconds faster than the 2 minutes 13 seconds recorded by C.J. Allen, which corroborates a maximum of around 98mph.
DID IT REACH 100MPH?
Flying Scotsman ran superbly on November 30 1934, averaging high speeds and setting journey times never before seen in the UK, but it did not reach 100mph on that day. The maximum speed was 98mph, as recorded and reported by C.J. Allen at the time, and as subsequently endorsed by O.S. Nock.
“THERE IS A SUDDEN JUMP IN THE CHART TO 100mph AND A JUMP BACK DOWN AGAIN TO A SPEED IN THE 90s, AS IF THE RECORDING PEN HAD BEEN JOLTED ”
Sir Nigel Gresley leads a hero’s welcome for the ‘A1’s’ crew - Driver Sparshatt and Fireman Webster - at King’s Cross on November 30 1934.