Let there be light

There’s a dark side to Paddington Station. While passengers on platforms 1 to 8 bask under the restored 1854 Brunel train shed, those directed to platforms 9 to 12 find themselves below a dark and sombre low-level ceiling that is blessed with ‘essence of Birmingham New Street’. And yet these are platforms beneath a spacious train shed – or at least that’s the theory. Anyone using Paddington since the mid-Nineties would be completely unaware of what is hidden above the gloom.

Span 4 – the section of roof above platforms 9 to 12 – was added to the original station between 1911 and 1916, providing more sheltered platforms for goods traffic and to accommodate a growing number of passengers. It was part of a major extension to the station, one that sought to meet the needs of the day without distorting Brunel’s original vision.

Major works to restore and refurbish the first three spans of Paddington’s roof were completed in 1993, but Span 4 has had to wait until now for its restoration.

Geography lesson
In the Nineties, the glass in the roof began to deteriorate so, in 1996, a temporary crash deck was installed above the platforms to protect passengers from any debris that might fall. This had to be all-enveloping but could not deal with everything below. There were particular problems at the buffer stop ends where there are station buildings of varying heights. The crash deck could not be adapted around them and was not waterproof, so a different solution had to be found. In the end, a tent-like structure was suspended over the buildings, a bit like a marquee. Whilst effective, this was to cause some challenges as the refurbishment work got under way.

There’s a bit more of the place’s geography to understand. An external high-level deck area is attached to the north-west side of Span 4. This covers platforms 13 and 14, supporting London Street – a road sandwiched between St Mary’s Hospital and the Paddington branch of the Grand Union Canal. Recently this was used by a parcels business but these buildings have now been removed. When Span 4 was built there was also a taxi ramp out of the main station, exiting through the haunch of the roof onto London Street.

Establishing a presence
Network Rail is spending more than £2 billion on renovating London’s stations. Part of that is focussed on Paddington and in particular on removing the gloom from Span 4. In January 2009, the company let a £35 million contract to Morgan Est for the complete restoration of the 1916 extension, along with the strengthening of the old parcel deck.

Chris Jones is Morgan Est’s project director and oversees the works from his offices now located in a cabin complex on the country end of the parcels deck. Chris has had some 20 years working on railway projects in the London area none of which, of course, have been blessed with spacious access and storage facilities. “But this one’s pretty good” he says, “although as a contractor I would always like more!”

In fact the old parcel deck is proving useful as a working area but it does mean that the offices have to up-sticks and move as the work progresses. In a contemporary twist of fate, the former taxi ramp – a facility for the Edwardian privileged – is now being used as a haul road by the construction team.

In keeping with history
Included in the roof works is the replacement of all the cladding, glazing and access walkways. These are the visible elements and have to be carried out in a way that satisfies the requirements of its Grade I listed status. Morgan Est, with its JV partners Morgan Ashurst, have a good working relationship with English Heritage and Westminster Council, ensuring that modern replacement materials are in keeping with the strict historical context. This has also been a challenge for designers WSP.

Within the roof, all the electrical and lighting systems are being renewed along with new CCTV and PA systems. Down in a basement area, a new switch room is being fitted out. Below the roof there are works on the platform surfaces with new paviors, tactiles and coping units. All in all, the western part of the station is being given a thorough makeover.

Crossrail is never far away. Parts of the project are specifically intended to facilitate the building of a major interchange on the eastern side. The existing taxi rank will be relocated from Eastbourne Terrace across to the parcels deck.

Challenge upon challenge
But of course nothing is straightforward. The temporary crash deck from 1996 has become a bit of a permanent feature. In the absence of anything else accessible, it’s been used to hang and attach various ‘things’ from, including OLE supports! Having been up for so long, its structural strength is uncertain so it can’t be used as a working platform for the works above. As a result, a second crash deck has been erected above it. This, along with the impressive forest of scaffolding around the station has been erected by Palmers Scaffolding.

The new deck now stretches over the entire length of the roof. It is slung from the main roof members and has a water management system. Diesel fumes became a problem for those working at the higher levels so a high capacity fume extraction system has been installed. The corrugated decking has been plated out with plywood sheets to form a network of walkways, minimising the risk of tripping accidents. Areas have been designated for storage and fire escape towers link the deck to the platform below.

Before the new deck was erected, another temporary measure had to be installed. The 100 year old glazing – the cause of the original problem – has not gone away and it is still just as brittle. The risk of glass dropping on those working on the crash deck had to be removed. This was done by erecting containment netting in the soffit of the roof. The only way to do this was to use abseilers.

By now, three or more layers of temporary works have been erected – the original crash deck, the new deck and the temporary netting. And there were even more complications as the new deck approached the area under the tent structure. Whilst this was suspended from the roof, it was fixed to points lower than the new deck. Bit by bit, the old tent was dismantled with even more temporary works being inserted as work progressed to make sure that the buildings below were still protected.

Attention for the steelwork
Even in 1916 there was a sensitivity to emulate the existing Brunel roof structure. Just above the springing level of the arched roof supports there is decorative cast iron tracery. These are simply bolted to the roof members. Each piece has been carefully numbered, taken down and sent away for restoration. Most are in sound condition and will need just basic blasting, cleaning and painting. A few have been damaged over the years and these will be recast from patterns.

Work has now started on stripping off the cladding and removing the glazing. Yet another layer of temporary works is needed for this – Palmers is erecting stepped scaffolding within the barrel of the roof. “These guys – Palmers Scaffolding, McNealy Brown doing the steelworks repairs and TI Coatings for the paintwork – are key to the success of this operation”, says Chris. “They’ve offices set up on site as there’s a constant need to liaise with them on something so complex.”

Even before the roof covering was started, there have been extensive steelwork repairs and painting. Steelwork at lower levels has been encapsulated with Envirowrap to contain the inevitable lead contaminants always found in paint of this vintage.

The existing cladding is a composite bitumen and steel sheet material with low levels of asbestos within the bitumen. As a result, removal is strictly controlled by specialists John F Hunt.

There have not been too many surprises for Chris and his team. They have not encountered any hurried World War II repairs and neither has the condition of the main roof steelwork given undue cause for concern. But nobody relishes the prospect of removing the old crash deck. For 15 years it has sat above idling HSTs and DMUs and is now coated with a sticky black residue.

With all the temporary works in place, new work is getting under way in earnest. Later this year, the stygian gloom surrounding Paddington’s platforms 9 to 12 will be lifted and passengers will no longer have to take a walk on the dark side.

Article courtesy of the rail engineer magazine.

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