‘PACIFIC’ CHALKS UP ANOTHER ‘EVEN TIME’ RUN BEFORE MAJOR FAILURE
Main line performance analyst Mike Hedderly describes Tornado’s flirtation with 90mph.
Tornado’s debut public 90mph run took place almost a year to the day since its successful 100mph trial. The train had been fully booked for weeks and loaded to 12 coaches of 417 tons tare and 455 gross. As passengers waited, there was a palpable sense of excitement among the throng on Platform 6 at King’s Cross. Network Rail had excelled itself in producing a remarkable schedule which involved averages of 71mph start-to-stop from Digswell Junction to the Grantham water stop, and again from Grantham to York. This equalled the average of the pre-war ‘A4’-hauled ‘Coronation’ non-stop express between London and York. The difference was that while the ‘Coronation’ loaded to nine coaches of 330 tons gross, No. 60163 would have to achieve similar timings with 12 coaches of roundly 450 tons gross. Altogether, 107.85 miles of the 188.50 miles to York were authorised for the ‘A1’ to run at 90mph; a much greater distance than allowed for Bittern’s 90mph runs in 2013. The civil engineer had imposed several 75mph restrictions at various points and, in addition, a 30mph restriction at Finsbury Park and 60mph at Oakleigh Park and Langley Junction, for bridges. The schedule of 3 hours 18 minutes for the 188.50 miles to York included a total of 24½ minutes of dwell time at Potters Bar, Digswell Junction and the Grantham water stop. This compares with 4 hours 43 minutes for Flying Scotsman with 400 tons on Day 1 of RTC’s ‘Great Britain X’ tour on April 29 last year, which included a total of 50 mins dwell time for passenger stops, pathing and water. Therefore the comparative timings with stops deducted were 2 hours 53½ minutes for No. 60163 at 90mph, compared with 3 hours 53 minutes for No. 60103 at 75mph. Therefore, even if covering a mile at 90mph compared with 75mph saves only 8 seconds, the pathing flexibility afforded by the higher speed is clearly demonstrable. From King’s Cross, Driver Paul Major and Fireman Dave Proctor were under the supervision of Traction Inspector Don Clarke. Leaving the ‘Cross’ 1¼ minutes late, Tornado made a confident start up the 1-in-107 through the tunnels to Holloway on the Down Slow line, but there was a brief slip coming out of Copenhagen Tunnel, which was quickly controlled. Then Driver Major eased the locomotive to comply with the
30mph bridge slack at Finsbury Park. Speed steadily increased to a maximum of 53½ at Alexandra Palace, at the foot of the long 1-in-200 climb through the Northern Heights to Potters Bar. Speed was held in the mid-50s on the climb, which enabled the 60mph limit imposed at Oakleigh Park to be respected without reducing speed. This would have been regarded as a good climb with 12 coaches in steam days for an engine starting ‘cold’ out of King’s Cross. The 19-minute schedule to the Potters Bar pick-up stop, actually quite a tight booking in view of the speed restrictions, was covered in 19½ minutes. The next 8.3 miles to a pathing stop at Digswell Junction, where the two-track section over the Mimram Viaduct commences, was run in 10½ minutes; a gain of three minutes on schedule after a maximum of 70½mph at Hatfield, still on the Slow line. After three timetabled trains had passed, No. 60163 set off ¼ minute early from Digswell, exactly opposite Milepost 21. With a 60mph bridge restriction at Langley Junction to come, speed was allowed to build up gradually until clear of the Welwyn Tunnels, when Tornado was opened up, topping the 1-in-200 at Woolmer Green at 56½mph. Now we were booked on the Fast Line all the way to Grantham. The first 90mph-authorised section was from Stevenage to Offord. A 1-in-200 descent begins just after Stevenage, then beyond Milepost 33½ it eases first to 1-in-264, then at 1-in-400 to Arlesey. After passing Stevenage at 67mph, speed had reached 73mph when brakes were applied, presumably for signals, reducing speed to 48½mph. We recovered to 64mph through Hitchin, which meant that two closely spaced 75mph bridge restrictions either side of Milepost 32¾, just beyond Hitchin North Junction, were passed at 71mph, while still accelerating. The ‘A1’ was blowing off vigorously as we accelerated to 84mph at the site of Three Counties station and 87½ through Arlesey, falling slightly to 85½ up a ¾-mile stretch at 1-in-264, then accelerating to reach the 90mph mark at Milepost 39½, down a 1-in-264. The brakes were suddenly applied through Biggleswade and we slowed to 52mph. Then from passing Milepost 43 at 45mph, we made an emergency stop at around 43.20 miles from King’s Cross. Driver Major reported that the reverser suddenly began to vibrate uncontrollably near Biggleswade so he brought the train to a stand. The 22.20 miles from Digswell had been run in 21 mins 47 secs. Sixtythree minutes of even time running from King’s Cross was over because the locomotive had suffered a serious mechanical failure. It transpired that part of the middle cylinder valve gear had come adrift, the combination lever and drop link having snapped (see separate story and Down Main).