Main line per­for­mance an­a­lyst Mike Hed­derly describes Tor­nado’s flir­ta­tion with 90mph.

Steam Railway (UK) - - News -

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).

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.