Mud, mud, glorious mud in South Croydon

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Written by Grahame Taylor for the rail engineer

Monday 1 August 2011. Just another Monday morning. The weather was fine. There was the weekend’s engineering work to discuss along with plans for the coming week. All was as usual.

Phil Barnes, Network Rail’s Current Operations manager sat with his colleagues in the morning meeting with his Route Director, as he does every Monday morning on the 12th Floor of the Network Rail HQ in Croydon. There seemed to be nothing unusual going on.

Except that…. had he been able to see East Croydon Station he might have noticed that something was odd. Trains going south were backing up. The railway was slowing down. All was not well.

Red lights

It is apparently bad form to keep looking at one’s Blackberry during a meeting. It might suggest that your attention is elsewhere. And so Phil gave his full attention to the meeting in hand.

When it ended, at about 11.15hrs, in a reflex action he turned his mobile device over and saw a flashing red light, then a string of texts, unanswered calls and emails all from Sussex Route Control Centre. Something had happened.

That was enough for Phil to go straight down to the control office on the first floor. No time to read or write emails. It was time to get the news from the horse’s mouth.

When everything is going to plan, railway control offices are quiet places with the odd phone call, controllers standing up and stretching, and general peace and quiet. This was not the scene that greeted Phil as he entered the room.

All the controllers were on their phones. There was definitely something up. There was urgency in the air – the faces of the Control staff bore looks of deep concentration.

They were dealing with something serious and, as Phil put it, “The atmosphere that I felt as I entered the room meant that my team were dealing with a major incident.”

But whatever the office had to contend with at that moment, it was as nothing compared to the situation that began to unfold during the rest of the morning………….

Burst main

But let’s wind back to just before 09.45hrs on that Monday morning. In a quiet park just to the South of East Croydon, water from a burst 12” cast iron main started soaking into the surrounding ground, searching for a convenient run-off.

Finally, it reached the drain of its dreams – the London to Brighton Line situated conveniently in a deep cutting. The water cascaded down the cutting slope and landed on the Down Slow line.

It’s worth explaining the track layout at this point. There are five lines running due north/south. The eastern-most track is the Down Slow, and alongside are the Up Slow and a reversible line.

The western lines are the Up and Down fast lines. Just to the south of this point are two junctions. One is the line to Uckfield and East Grinstead and the other is the line to Caterham and Tattenham Corner.

Around 57 trains travel on this stretch of railway in an hour.

Moving ballast

At 9.53hrs a train driver reported in to the signaller that there was water and ‘moving ballast’ on the down slow. With the driver mentioning ‘moving ballast’ this was enough for the down slow to be closed immediately.

The next steps that Mark Wyborn, the duty Network Rail Route Control Manager, took at that time were critical. He sent an Operations response team and the Signalling response team to investigate on site.

Those response teams arrived at 10.05hrs – just a little over 10 minutes after the first report. Mark also contacted Thames water and instructed his Train Running Control team to start plotting service alterations based on a reduction of network capacity.

At 10.10 a message came back that water was above the conductor rail height, which meant that at 10.11hrs both slow lines had to be closed.

Fortunately all trains were brought to a controlled stop – that is, at a signal – and, in this case, at a station.

So, at this point, all trains were being routed over the remaining three lines.

At 10.22 there was a report of an earth slip.

At 10.30 Mark convened a conference to get the latest reports from site and agree with the controlling signal box the revised train plan formulated by the control team.

After getting a brief overview of the current state of play from Mark, Phil arranged for a further conference. This conference was to set up the ‘Gold Command’ structure to manage the emergency as per the Network Rail Emergency Plan. At this time, Phil was appointed the Rail Incident Commander.

All stop

At 11.28hrs an engineer reports in from site and at 11.33hrs all lines are lost. The main artery between London and Gatwick Airport and the South Coast has been cut off. This is going to have an immense effect on the travelling public.

Phil vividly recalls, during the early stages of the incident, a call with Thames Water, owner of the offending water main, who was being encouraged to turn the water off as quickly as possible.

“I am losing my railway…..” he told their controller, and then, after a response that agitated him further, Phil cut across with, “No – you don’t get it. I can no longer SEE my railway!”

Modern technology in the form of mobile phone cameras enabled those on site to send images of the developing situation direct to the control room so Phil could actually watch his railway disappear underwater.

The water was finally turned off at 12.55hrs, but of course continued to flow for a further 40 minutes as the pipe emptied and water drained out of the park.

MudslideNR
Photo: the rail engineer.

Taking possession

At 14.00hrs steps were made to convert what was a line blockage (taken in an emergency) into a T3 possession – a recognition that this was now an engineering site which would need to the use of RRVs (Road Rail Vehicles).

Simon Brazier runs the Civils and Buildings part of Infrastructure Projects for Network Rail Sussex and Wessex, and the East Croydon area falls under his control.

He too was in a meeting which he left to take a call from the Route Geotechnical Engineer. He was told that there had been a water main failure in the park adjacent to the railway and that this had taken a large proportion of the cutting face down onto the track. Mud and silt covered four of the five lines and the whole of the railway was flooded.

The railway was closed. He recalls, “I was called out of a meeting to take the call in late morning, jumped into a car and drove up to East Croydon. I have had phone calls like this before. It’s not a completely unknown situation but normally these emergencies are weather related!”

He walked down to the site from the Station. It was eerily quiet with no trains, but a number of people from the maintenance organisation were there armed with shovels ready to have a go at clearing the track.

But, faced with 2500 tonnes of silt to shift, they knew that they would have very little impact. So a plan was drafted between the various teams on site.

The maintenance organisation were to clear the silt using plant and machinery supplied from their local depot and supplemented by additional RRVs organised by Simon and his team who were themselves remitted to affect a repair to the cutting face.

The water had been turned off at this stage and the water had stopped running but parts of the cutting face were falling out as they considered their solution.

Calling BAM

Historically, Network Rail had a framework contract with BAM Nuttall. The contract had, in fact, just finished and although the new contractor was on board they were not in a position to mobilise quickly enough.

So BAM was used as they were able to respond very quickly because of all their previous experience.

One of their earthworks contract managers was available and was able to get to site reasonably soon. At their site meetings they decided how to remove the material and how to make safe and re-profile the cutting slope.

Regular teleconferences with the operations team were used to discuss strategies and timescales.

Simon recalls the site arrangements. “Rail access for RRVs was from South Croydon which was relatively close. We brought a long-reach excavator through the gates of the park to the top of the cutting.

“Some of the gates had to be removed so that it could get in and gently trundled across the park. The excavator needed to be relatively light otherwise it stood a chance of joining the rest of the mud and sliding down the bank.

“The failed material began to be removed at around 7pm. The excavator worked for about 14hours to completely re-profile the slip area.”

Clearing the spoil on the track was a joint effort between the maintenance section and BAM who provided the RRVs from subcontractor Keltbray.

Rob Pearson, BAM Nuttall’s contracts manager, Colin Haytor Network Rail’s senior construction manager, and Simon were the coordinating presence on site.

Pots of damage

In parallel to the spoil removal there was a need to repair damage to the signalling and to the third rail. Many conductor rail insulators (pots) had to be changed because the silt contamination would have been almost impossible to remove. The land slip knocked over parts of the conductor rail, wrecked the track ballast and filled up the drains.

Referring to similar emergencies Simon knows that, “It’s the knowledge rather than the kit that’s critical. You can usually get kit from some sort of source, it’s getting the experience to site that makes all the difference.”

Although by this time many routes into London and around Croydon and Gatwick were gridlocked, Simon was able to get staff in and out of the site via the ‘side entrance’ – that is via the Kent route.

There was, of course, 24hr working until the job was finished. Afterwards there were follow-up works like removing trees and installing drainage to the cutting face. All in all there was work on site for about 10 days.

Reopening

Back in the Control Office, the primary focus was to get something open, and this they did by 18.03hrs on the Monday evening when the fast lines reopened. These had been affected more by water than by mud.

Network Rail and its customers First Capital Connect and Southern worked through the night to construct a new train plan based on the restricted track layout of just two lines through one of the busiest networks in the country.

The media management was excellent with images of the mudslide being beamed onto the large passenger information screens at Gatwick and at the major London stations and by printed posters erected at many stations on the Sussex network.

By the following morning the public had got the message. Trains on the Tuesday were strangely quiet.

With the signalling tested four lines reopened at 17.00hrs Tuesday which was enough to run a full service. By 04.30hrs Wednesday morning there was full network with no speed restrictions.

Phil summarised that “Some real positives came out from the South Croydon landside. There were no passenger accidents, no trapped trains, no workforce injuries and, after thousands of tonnes of mud and silt were dumped on the railway, a full network was available within 40 hours – a real testament to the teamwork and effort shown by all of those involved”

But, Phil adds wryly, “After such a significant incident that led to a major impact on the journey experience for our travelling customers, it is absolutely imperative to reopen and run a perfect service the following day.

“But as Wednesday got underway, there were reports of gas canisters on fire near the line side at Sanderstead. At noon there was a train failure and, sadly, a fatality at Clapham Junction in the evening. You really couldn’t make it up!”

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