Return to Archive -by date - by topic.
After so much had been achieved, the programme fell apart in the final weeks
When I went to see the slab track being laid between Prestbury and Hibel tunnels in the Stoke blockade back on August 20, everyone on the home team was bullish. In particular, the permanent way snagging works were 98% complete and tamping 100% complete
Meanwhile, Informed Sources were reporting problems with track quality, and in particular track stressing certificates that did not seem to match the stressing temperature in the rail as laid. Remembering that rail was being laid on the Stoke Blockade through the August heatwave the Neutral Rail Temperature (NRT) of 27 degrees C might have been exceeded for long periods.
Remember that while at temperatures below NRT you can pull the rail to give the correct stress, above 27 deg C you can't compress it. All you can do is wait for it to cool down. And waiting is the hardest thing to do on a high pressure, high profile project.
So, fast forward to the handover date of 27 September and Network Rail asked the Train Operatring Companies for another 24 hours grace with the route reopening for service at 04.00 on Monday. As late as 15.00 on Sunday Network Rail was saying that the route would be open to the new time. Then during the evening TOCs were told that another week would be required. The formal confirmation was issued at 21.00.
This did not go down well with the TOCs who were all geared up to start running trains with the Monday morning peak. Mind you, two old hands had presciently kept the buses which had been maintaining services during the blockade on stand-by just in case.
It was a PR disaster, with passengers rolling up expecting to have a train again and finding the buses waiting. Even more embarrassing, according to our man on the spot Mr Miles, Network Rail had sent out a press release before the weekend, embargoed until 06.00 on Monday, headed “Industry says ‘thank you' as Stoke works end” and which declared the route to be open again. Local radio stations ran the story anyway, abruptly changing the story when a new release headed “Extra week for finishing touches at Stoke” was circulated. All very 1984.
But how, given the planning, machinery, manpower and money involved, not to mention Bechtel's hard driving project management and a 19 week blockade, could it have all ended with the bride going into labour in the vestry? On 9 October I spoke to Network Rail West Coast Project Director James Martin and Tom McCarthy, Bechtel's man on the job.
According to James, the last straw was the loss of a complete tamping shift on the Sunday due to equipment failure. Nine machines had been scheduled to complete tamping of the relaid track, but so many failed that the shift was effectively lost. Why did so many machines fall down? Quite simply, in Tom McCarthy's words ‘we literally worked the tampers to death'.
Once the trackbed had been cleared and the new ballast was coming in, the tampers had been ‘running 16 hours a day' week after week. One reason for the high tamper work-rate was the introduction of a new method specification aimed at producing a highly durable formation by building up the ballast in levels with intermediate tamping to consolidate the track bed.
In between layers the alignment was surveyed and measured, so that the tampers were working to a design level rather than correcting imperfections in existing track. James Martin reckons that the tamper work rate during the blockade was probably greater than the machines had experienced on European railways.
But if tamping and snagging had been completed back in August, why where nine tampers supposed to be out the day before the line was due to open? And, according to Informed Sources, had the tamping been completed the route would have reopened with extensive temporary speed restrictions of 30/60 (30mile/h freight/60mile/h passenger) between Stoke and Macclesfield and even lower, possibly 20mile/h between Macclesfield and Cheadle Hulme.
With an extra week's work, when the line eventually reopened on 4 October , there were only two TSRs in the 50 miles and one was linked to the overhead line electrification. The other was for a transition between plain line and a set of points.
Under the original programme, the last fortnight of the blockade would have seen the track virtually ‘wheels free' during commissioning of the signalling and re-energisation and testing of the OHLE. In the event the signalling was signed off for non passenger use at 04.00 on Saturday and would have been available for passenger operation at 06.43 on the Monday' According to Tom McCarthy, ‘we held to the wheels free period but we had some final tamping to get speeds up between Stoke and Kidsgrove and that's where the tamper breakdowns affected us'.
Which is where we come back to the reported track quality issues on the 38 miles of per way relayed by Jarvis. In addition to testing showing discrepancies between the recorded stressing temperature and that revealed by subsequent testing, some of the welds needed rectification work.
James Martin only confirm that there have been ‘particular problems' over rail stressing records from ‘one of the (renewals) contractors that is a concern'. As a result, he says ‘we took the only responsible course you can take – 100% retest'.
James is commendably protective of his contracting teams and doesn't want their morale damaged by adverse reactions to the late opening overshadowing the real achievem,ents. ‘It was traumatic for everyone involved' he says. ‘There were a lot of tired people that day and we nearly succeeded'.
While he would not go into details of the test results, and cautioned that the technique used is a very simple bending test with the rail unclipped from which internal stress can be calculated, in his view ‘it is still a legitimate test and it legitimately proved that some of the data we had was not correct'.
So total testing plus any restressing necessary had to be added to the work programme after snagging and tamping had nominally been completed. Hence the last minute tamping.
Stoke Blockade also saw the first extensive use of the new mobile flash-butt welding road/railer plant. This is a sizeable piece of kit which tows its own generators and had to be fitted into a railway where works trains were still running. With less access than planned, the proportion of Thermit welds increased.
Even so, Martin claims that more mobile flash-butt welds have been made during the blockade than on the rest of the network since the equipment became available. McCarthy adds that this was a new technique and output improved over time. Weld quality is described as excellent. However a number of faulty welds had to be replaced which, depending on temperature can involve restressing
Of course, renewing a railway is a bit like restoring an old vehicle. When you start using the angle grinder the rust is always worse than you expected. Similarly, when you clear the ballast the underlying formation will have unexpected nasties even though test pits have been excavated in the ballast every 100 yards. Thus to the remedial work on the track should be added an increase in formation works from the planned 37,000 yards to 46,000 yards.
So, overall, James Martin and his teams are looking to build on the positive lessons learned from the Stoke experience. He points in particular to the ride quality being obtained from the combination of extensive formation work done with the aim of achieving a 30 year life and some excellent alignment under the supervision of an old school civil engineer. And we now know that Bechtel managers put their trousers on one leg at a time like the rest of us.