HomeGeneral InterestThe Kilsby Genie
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Here at Rail Engineer magazine, we seem to have a thing about tunnels – especially tunnels with blocked drains. Back in 2012, we scrambled through Dove Holes in Derbyshire. For a Christmas treat in 2017, we covered Sevenoaks tunnel. Obviously so impressed, we went back in 2018 – although it might have been that the author had forgotten that he’d written about it only a year earlier!

Same themes – long wet tunnels, clogged drains, bad track.

So, how can we explain the attraction of Kilsby tunnel? It, too, is wet. It, too, is long. It, too, has track issues and, of course, it, too, has a blocked drain.

All the boxes are ticked but, by now surely, these alone can’t be enough.

And what’s the strange title all about?

Groundwater and chemistry

Let us, for a moment, step back (carefully) and look at some basic facts.

Kilsby tunnel is on the southern part of the West Coast main line (WCML) just to the south of Rugby. When it was opened in 1838, at 2,432 yards (2,224 metres) long, it was then the longest tunnel in the world.

Machinery working inside Kilsby tunnel, viewed from above down one of the tunnel’s massive vent shafts.

It was a challenging tunnel to construct, the work having been frustrated by running sand and groundwater. One hundred and sixty-two years later, the groundwater, at least, is still causing problems. With a high mineral content, anything static that is drenched in water percolating from the tunnel walls and soffit will gradually acquire a coating of calcium carbonate – and probably other ‘stuff’ as well. The track ballast is static and, over time, becomes calcified. The same thing happens to the drains. Everything turns to something as hard and impenetrable as concrete.

This has been going on in Kilsby tunnel for generations. The central drain, in parts, ceased to function. The track was not drained, and track quality suffered. In recent months, in order to reduce the number of ‘rough ride’ reports, an Emergency Speed Restriction of 90mph had been imposed – from a normal linespeed of 110mph.

‘Something had to be done’ as Network Rail was being charged hundreds of thousands of pounds in delay penalties on one of the busiest parts of the national network.

Empty trains

In normal times – and early 2020 was not normal – the repairs to the drain would have taken years to organise. Many repair attempts had been made, but with only 16-hour rules-of-the-route possessions available, these have generally been ineffective.

The idea of a long blockade of Kilsby had, until now, been in the rather difficult pile. It wasn’t going to happen any time soon.

But, as has just been mentioned, early 2020 was not normal. This was the time of the Covid-19 pandemic, when everyone was encouraged to stay at home and not use public transport. By and large, the public did stay at home and very few travelled on the trains. Indeed, the normal passenger loadings of the Avanti services were in single figures or barely double figures. A special, deconstructed timetable was in use.

Rising to a crisis

This is the point when a mundane story about a wet tunnel with a blocked drain takes an abrupt turn into the unexpected. It does so because the rail industry also made an abrupt change in the way it normally worked. There was a seismic shift.

Maybe it was as a result of a chance remark made at the right moment. Maybe it was just a general realisation that now was the right time to suggest the unthinkable, to think about a complete blockade of the WCML – now!

Apart from during times of crisis, railway projects tend to evolve cautiously. But this was a crisis and an opportunity. And the railways always rise to a crisis!

Timetabling issues

Before anything was done on the ground, there were conversations to be had. The parties involved with this part of the WCML were Network Rail, Avanti – its trains use the ‘old’ line straight through to Rugby and beyond – West Midlands Trains, LNWR and the freight community, which run around the Northampton line.

With a tentative proposal that the line through Kilsby be blocked, Avanti was asked to comment on impacts to their services. The diversion through Northampton adds about 15 minutes to a mainline service and it was this extra time that affects both turnround times at terminuses and unit usage.

Breaking out the old drainage pipes.

Quick analysis showed that the extra time actually helped Avanti in some locations, because terminating trains could be held in a platform instead of having to shuffle out of the way until the return departure time. On some longer services, an extra unit was needed to maintain return timings.

Network Rail looked at the pathing of Avanti trains and points of conflict with slower trains. It was found that, with the less onerous demands of the deconstructed timetable, the Avanti trains could just follow each other via Northampton with very little interruption of the West Midlands or LNWR services. This worked so long as enough time was built into the revised Avanti running.

It is tempting to think that this exercise was an application of an existing contingency plan for when the WCML is blocked because of a major incident. It wasn’t, as contingency plans are based on normal timetables. The Kilsby blockade timetabling had to be started from scratch.

Deconfliction, a process (as the name suggests) of determining where/when train paths conflict, can be a lengthy process, but, because there were fewer trains, one of Network Rail’s signallers ran the simulator and put a ready-reckoner deconflictor together. Every time a conflict was identified, a regulating policy was decided. This boiled down to a view that an Avanti train would go first and the WM train would be two mins late. “We’ll just live with it.”

Shopping list

The mood was positive. In fact, the mood can be summarised in the words: “Do you know what, we will be kicking ourselves in three months’ time if we don’t take this opportunity.” From that point on, the project had a life of its own and there was an almost collegiate approach to make it all work.

One of the mobile ventilation fans.
A moment of socially distanced silence for VE day.

The length of the blockade depended on the length of the shopping list, so engineers looked at the core requirements. These were 800 yards of drain renewal, 870 yards of track renewal on the Down line and 650 yards on the Up line.

The track renewals engineers boiled this down to a requirement for a ten-day blockade – from a Monday. What emerged through further rapid discussions was an offer of two full weeks with the weekends at each end. The idea was to engage in maintenance works at the weekends and let the drain and track renewals team work in the intervening time.

Thus, the project was born, industry partners were on board and all was set for a hectic few weeks.

Feeding frenzy

Of course, as word spread that there was going to be a blockade on the WCML, engineers of all descriptions started to amass like bees round a honeypot. Here was an opportunity to carry out work that couldn’t be missed.

To control this feeding frenzy, the blockade was split into four logical worksites – A, B, C and D. Worksite A was the tunnel, with trains coming and going from the North. Worksite B was a mix of renewal and maintenance and therefore had a management structure that controlled it in a renewals-based manner. Worksites C and D, to the south, were predominantly maintenance and so were more ‘high-street’ environments, where people booked in and out and were able to do maintenance and ad hoc activity in a less ‘regimented’ manner.

Whilst many industry norms were being broken in the birth of the blockade, the actual worksites conformed with known and accepted activity templates. When work is planned within a tight timescale, industry processes and protocols have to be used to give the practical impression that it’s business as usual. People are then working in a manner that they recognise.

On the ground

All this happened at a strategic level. Closer to the ground, there was also much activity and it’s worth seeing how everyone’s efforts blended to ensure a successful outcome.

Symon Reid is Network Rail’s infrastructure maintenance engineer. He manages the infrastructure from the 34 mile post in the Cheddington area, near Aylesbury, to just south of Coventry on the Coventry line and just south of Shilton on the Trent valley lines. Kilsby is on a critical two-track section between Rugby and Milton Keynes.

“We’d been doing some drainage inspections in the tunnel and found a run of drainage of about 150 metres that was completely collapsed and clogged with all sorts of silt and calcified ballast.

“Track defects were increasing and we were building up a project to mend the drainage, but the only way to do it was to remove one of the roads and break out the drains completely, to allow it to be renewed.

“The tunnel has had water problems for many years. There is a very high water-table in the tunnel and, with the drain in the six foot being clogged, it is easily overwhelmed.”

The idea of a bold project to tackle the drain was being hatched, but it came as a ‘surprise’ to hear that, not only was a blockade agreed, it was also happening in five days’ time!

His Northampton maintenance team was mobilised and made the most of the extended possession times on this intensively trafficked part of his network.

The phone call

Stevie Welsh is the senior programme manager with the CRSA (Central Rail Systems Alliance) at the Aston depot. His involvement with the project started with a telephone call. There was a simple request. “If there was a blockade of Kilsby tunnel for 15 days, what would we be able to do?” At this stage there was no mention of forward timescales – it was a routine enquiry perhaps. Conversations took place, past specifications were researched, bar charts were drawn up. The reply to the query was sent in.

Then came the start date. Saturday 2 May – in nine days’ time!

“The weekend prior to the start, the team went into the tunnel and did a site walkover to check the specs on the ground and to get the job marked up. There were the plant companies, the labour suppliers, signalling engineers, overhead line engineers and the track maintainer, along with Manta, the tunnel ventilation fan supplier.

“Trial holes along the length of the drain were dug, to see how the two tracks were affected.

“Bringing everyone together gave us the confidence that we could deliver all this work.

“The biggest unknown was the old drainage system, because we didn’t know how difficult it would be to remove. The renewal of the drain would be fine. The renewal of the track would be fine.”

Critical component requirements included all the items needed to install the drain – the pipes, catchpits etc. These were placed on order with the manufacturer, Aqua, which changed its production schedule specially to accommodate the Kilsby job.

The design scheme was by PBH and was based on works previously carried out in the tunnel.

All’s well – until it isn’t!

It was known that the existing drain was of concrete construction and that it could cause difficulties during removal. The team was encouraged by making rapid progress at first, when the first 100 yds went very smoothly………… until it didn’t.

Hydraulic peckers had to be used and, even then, progress became frustratingly slow. It was time to regroup. Bar charts were modified. Contingency times were absorbed. Traincrew times were changed and all the companies involved were put on notice that shift arrangements were likely to be amended. A demolition job that should have taken three days extended to six.

It was time for everyone to hold their nerve. The main priority was to renew the drain. Ending the blockade without renewing the drain would mean that the track would rapidly deteriorate and the prospect of getting another blockade anytime soon was vanishingly remote.

In the end, those tackling the stubborn drain began to adapt to the difficulties and progress accelerated. With the drain out of the way, the remaining tasks – drain and track renewal – were all familiar and predictable. Tensions eased and the possession was handed back at 06:23 on Sunday 15 May, with all work completed as planned.

Covid-19 precautions

The Kilsby project was a direct result of the Covid-19 emergency. Without it, passenger numbers would not have plummeted and there would never have been a discussion about a two-week blockade on the WCML in early springtime.

However, with the opportunities came limitations and obligations. Just because the blockade had been agreed didn’t mean that the virus had somehow gone away. The threat still remained and had to be managed.

Social distancing – keeping two metres apart – had to be maintained. Fortunately, disciplines had evolved over the previous weeks and these were incorporated in the work patterns.

Work in Linslade tunnel, a single bore tunnel further south on the WCML, a fortnight earlier had also been carried out under Covid restrictions and measures were found to be practical. These involved reminder signs, sanitisers around the compound area and a removal of sitting down messing facilities to avoid close contact.

Covid marshals, present on site and also at the compound area, made sure that everyone social-distanced. There are tasks where two-metre distancing was not possible. For these activities, air-fed masks were available.

Maintenance work has had to work with Covid restrictions from day one of the lockdown. Again, a mix of distancing and PPE is used. Asked whether this has had an impact on productivity, Symon’s reaction was that, counter-intuitively, it didn’t seem to slow work down at all.

Strategic reflections

James Dean, route director for WCML South at Network Rail, reflected on the whole project.

“With the wider industry driving devolution to get route structures closer to customers – train operators and freight – we felt that this one, really unusual approach to things had actually created a very devolved approach to life,” he commented.

“What we found was that we had contractors, operations, maintenance, track renewals, the supply chain – we had technical authority – all working in a very quick, fleet-of-foot, prioritised, customer-focussed manner to deliver something that was extraordinary.

“The biggest lesson learnt is that we have found how to work like that. It’s a really good indicator of what can be done when we devolve things more, down into route structures within Network Rail.

“Beyond any doubt, we changed ways that people thought things could be done. Take, for example, ‘simple’ things like procurement. If we need to be doing things like this on a regular basis, we need to look at our procurement methodology. We need to look at how our frameworks with our suppliers can be set up. We need to understand how chains of command can be made slicker.

“Another powerful example was drafting the scope and remit for the work. We sat down and, within a day or two, had written a fairly detailed summary for the contractor to go and deliver. That would take six months normally – it’s just crazy when you think of it. But those sorts of things where people just sit down and have a conversation, rather than a long drawn out GRIP process, is where I think we really identified the benefit of people working in a much more localised manner.”

Gus Dunster, executive director of operations at Avanti West Coast, concurred: “We are pleased to have played an important part to facilitate this unique opportunity for Network Rail to access and maintain the railway between Rugby and Milton Keynes.

“This is a notoriously difficult section of the network to maintain, due to the density of traffic that it carries, and speed restrictions have frequently needed to be applied because of this.

“The scale of work undertaken would usually involve months of careful planning but, with a reduced timetable in operation due to the Covid-19 pandemic, we were able to do this in a matter of days. Working together with Network Rail, we could facilitate access for the project, while ensuring our vital services were protected for key workers and those making essential journeys. We put customers at the heart of our plans and diverted our trains via Northampton to keep them moving and minimise the impact to their journeys.

“The project has been a great achievement in unprecedented circumstances and, with 292 of our trains passing through Kilsby Tunnel on a typical weekday, the restoration of the line will improve reliability for many customers for years to come.”

There we have it. Another story about a wet tunnel with a blocked drain. But the parallel tale is about how railway decision-making can be slick, can be focussed on customers and can achieve remarkable outcomes.

It’s not rocket science. We’ve just seen, despite the national emergency – or maybe because of it – a full-scale working model of how effectively the railway can be run.

The genie is out of the bottle!

Grahame Taylor
Grahame Taylorhttp://therailengineer.com

Structures, railway systems, railway construction, digital data

Grahame Taylor started his railway career as a sandwich course student with British Railways in October 1965, during which he had very wide experience of all aspects of railway civil engineering.

By privatisation, he was in charge of all structural and track maintenance for the Regional Railways’ business in the North West of England.

In 1996, he became an independent consultant, setting up his own company that specialised in the capturing of railway permanent way engineering knowledge using the then-new digital media. As a skilled computer programmer he has developed railway control systems and continues to exploit his detailed knowledge of all railway engineering and operations.

He started to write for Rail Engineer in 2006, and became editor two years later. During this time, he has written over 250 wide-ranging articles and editorials, all the while encouraging the magazine’s more readable style of engineering reporting.


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