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    The restoration of TynemouthRailway Station canopyJames Miller MA,CEng, FICE,FIStructEConservation Accredited Engineer and Technical Director, Ramboll, London,UK

    Tynemouth railway station was built in 1882 and characterises the zenith of the railway age in Britain. The elegant

    cast and wrought iron roof is a Grade II* listed structure, an important regional example of its type. It fell into

    disrepair in the 1960s through lack of maintenance and by 2008 the larger part of the eastern canopy was in an

    appalling state with widespread corrosion. This paper describes the restoration. Basic calculations of capacity were

    undertaken prior to survey, to inform observations and the measurements of residual thickness. A comprehensive

    survey of defects was carried out and a document outlining the conservation philosophy was compiled, which formed

    the basis of the listed building consent. Almost all iron columns were found to have cracked near the top of the

    casting. Replacement of columns was considered to be too great a loss of historic fabric and unnecessary; the reasons

    for this are discussed. The paper concludes with an appraisal of the projects successes.

    1. Introduction

    Tynemouth Railway Station is located on the north-east coast

    of England, east of Newcastle. When first built in the late

    nineteenth century it was a major destination for passengers

    travelling to the fine beaches on the Northumberland coastline,

    but 100 years later, in the 1980s, it had become a through-

    station for short, two-coach trains on the local Tyne and Wear

    Metro line, and had deteriorated into an appalling condition.

    The station is owned jointly by the private development

    company Millhouse Developments Limited and local authority

    North Tyneside Council.

    Although many schemes for restoration had been proposed, it

    was not until 2008 that the funding was assembled. Monies

    were contributed by the local authority, central government,

    other public bodies and the developer. This paper describes the

    history of the project and the details of restoration, inparticular outlining the steps taken to follow good conserva-

    tion philosophy in the execution of repairs.

    2. History

    Tynemouth lies on the north side of the river about 8 km east of

    Newcastle. The first railway along the Tyne was opened in 1839,

    but did not directly serve Tynemouth itself. The architects and

    civil engineers for this early line were father and son, John and

    Benjamin Green. The building of the railway was no small task,

    and his effort, including the design of an earlier timber-structured

    Ouseburn viaduct, earned Benjamin Green the Institution of

    Civil Engineers Telford Silver Medal (Leyton, undated).

    Tynemouth itself experienced four phases of rail development

    over a relatively short period of time, serving both industry and

    local community (Wells, 1989). This began in 1847 with an

    extension of the Newcastle and Berwick Railway. In 1871 the

    countrys Bank Holidays Act was passed, bringing to life the

    concept of holidays for all and, in part spurred on by new-

    found leisure, there was a wave of excursion development: the

    sea piers and airy seaside stations to welcome holiday-makers

    to the coasts of England. The current station at Tynemouth

    was built in 1882 to designs by regional architect William Bell

    and it characterises the zenith of the railway age in Britain.

    Tynemouth Station itself was conceived as the jewel in the

    necklace, as the rails from the north were linked to the line

    arriving east from along the river in the last of the four phases,

    the station lying on the curve in the alignment that connected the

    two (see Figure 1). The broad, elegant cast and wrought iron

    station canopy was built to welcome people from the area

    around Newcastle as they discovered the beautiful beaches belowTynemouth Castle and around Whitley Bay. The passenger

    station had through-lines to take trains further up the coast, but

    two platforms were built for trains that terminated, shuttling to

    Newcastle and back.

    The heyday of the station was from the time of opening until

    the outbreak of the First World War. The line to Tynemouth

    Station was one of the first in Britain to be electrified when, in

    1904, American-style electric multiple units were purchased to

    make the shuttle journey, powered by the new Carville A

    superheated steam turbines on the Tyne, which were the

    worlds largest at the time. The increase in car ownership afterthe Second World War saw use of the branch line decline;

    Tynemouth survived the cull in the 1960s, but the sprawling

    station canopy was by now deteriorating rapidly and large

    Engineering History and Heritage

    Volume 167 Issue EH3

    The restoration of Tynemouth Railway

    Station canopy

    Miller

    Proceedings of the Institution of Civil Engineers

    Engineering History and Heritage 167 August 2014 Issue EH3

    Pages 136146 http://dx.doi.org/10.1680/ehah.14.00002

    Paper 1400002

    Received 09/01/2014 Accepted 06/05/2014

    Published online 30/06/2014

    Keywords: rail & bus stations/rehabilitation, reclamation &

    renovation

    ice | proceedings ICE Publishing: All rights reserved

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    parts of the glazing were stripped and replaced with corrugated

    asbestos-cement sheeting.

    When a new metro system was proposed in the 1970s to link

    the wider Newcastle conurbation and outlying towns, the line

    through Tynemouth was a natural choice to include as part ofthe network. However, the new two-car trains were a fraction

    of the length of the original platforms and, although repairs,

    redecoration and re-glazing were carried out to the smaller

    western canopy and the centre section of the eastern canopy,

    the north and south ends were fenced off from public access

    and left to decay, exposed to the coastal weather. Many people

    know of the station for the popular flea market that started in

    1981, with hundreds browsing on the weekend stalls, but the

    revenue from this activity was minimal. A number of planning

    applications were put forward through the 1990s to permit

    restoration and development, at a time when commercial

    enabling development was often put forward as a solution forailing heritage fabric, in effect selling off part of an estate as a

    solution to create capital for restoration, but this concept was

    met with strong reaction from community and public bodies

    alike. None of the solutions met with sufficient local support toproceed, and the canopy decayed further, with dwindling hope

    of rescue (North East Civic Trust, 2001).

    The station is listed Grade II* because of its significance as an

    outstanding example of a regional excursion station, which in

    terms of significance puts it in around the top 5% of UK

    heritage assets.

    Questions over the structural integrity of the bolted connec-

    tions to the cantilever sections of the roof, which hang towards

    the live railway and 1500 V DC (direct current) overhead lines,

    led to erection of unsightly temporary scaffolding supports.This was a clear visual reflection of the very poor state of the

    fabric, and in 1988 the structure was put on the English

    Heritage at Risk register, emphasising the urgent need to

    develop new uses for the site to create sustainable revenue. In

    2008 it appeared on the front cover of the Heritage at Risk

    review and efforts were redoubled to find a permanent

    solution.

    A many-stranded funding route became available in 2009,

    when the third wave of government Sea Change funding for

    coastal settlements and fabric was linked to monies from the

    Heritage Lottery Fund, English Heritage and both local

    authority and developer to build sufficient reserves to attempt

    the restoration of the severely decayed sections of canopy;

    these are shown as grids 19 and 1424 in Figure 2. An

    essential part of this was also the granting of planning

    permission for modest, single-storey, additional retail and

    community buildings within the existing station complex, to

    enhance revenue. These were required to be of exemplar design

    to fit the historic setting. Architect for the new-build

    application was Hodder Associates. With provisional funding

    now in place, a programme of works to isolate the cost of

    works and undertake the project was commissioned.

    3. DescriptionTynemouth is an attractive station. Dating from the late

    Victorian period, a decade before the introduction of early

    steels, the use of cast and wrought material is seen at its best, in

    a modest, regional scale. The ironwork is constructed to a

    repeating design pattern of cast columns, cast decorated filigree

    brackets and wrought lattice valley beams and longitudinal

    arch trusses, in plan measuring approximately 150 m625 m.

    However, being located on the gentle curve as the railway turns

    from east to north and with the canopy varying in width, the

    geometry changes quite subtly, creating an elegance in the

    overall structure. It is not vast like the magnificent Grade I

    listed, cathedral-like station roofs at York or Newcastle,having a free height of columns of just 4 m to the underside of

    lattices, a longitudinal span of around 7 m and a roof pitch of

    30 . It has the feel of a huge covered market, earning it the

    Figure 1. Historic Ordnance Survey plan (1894)

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    nick-name of the Covent Garden of the North, an illusion to

    Londons famous Victorian covered flower market, and indeed

    the proportions of the space are not unlike the London landmark.

    The restoration was confined to the eastern canopy roof, which

    is significantly broader than the western, as it was built to

    cover the terminating platforms from Newcastle and further up

    the coast. The station has four column grids on roughly

    concentric curves, offset evenly from the tracks, and 24 grids

    that fan perpendicular to the tracks.

    By the time the station was built, engineers and architects had

    long since come to appreciate the relative structural value of

    cast and wrought iron and the economy of fixings. By the

    1880s structural bolting had appeared as normal practice butthe cost of bolt fixings would continue to make it unreasonable

    for them to be used at works for connecting parts. At

    Tynemouth individual components have therefore been riveted

    together into structural assemblies, such as lattice beams andarch trusses, and these were bolted together on site in the final

    assembly, with structural bolting at all element interfaces, such

    as angle purlin to arch truss, arch to valley lattice and lattice to

    cast column.

    The valley gutters are non-structural, sitting on the lattice

    beam, and these are formed as substantial segmental iron

    castings, with one standard unit and several specials for

    corners, down-pipes and infills. Rainwater was discharged

    from these down the unlined, hollow cast columns on two of

    the four longitudinal grids: the one nearest the tracks and the

    third one back. It is shot sideways from the base by way of acast spigot into the simple vitrified-clay drainage system.

    The canopy is built into a single-storey red-brick station

    building to the east, currently occupied by small retail shops, a

    restaurant, a cafe and a private health clinic. It is these that the

    planned building development will augment, to create a site

    with a greater, more sustainable foot-fall and revenue.

    4. Survey

    In 2009 the client appointed Gifford LLP, now Ramboll, to

    undertake an initial survey of defects with recommendations

    for repair (seeFigures 3and4). This was used as the basis of a

    listed building consent, to inform the cost plan and to provide

    a basis for tendering the works. Ramboll was also instructed to

    oversee structural works during implementation. Heritage

    architect for the work was Lathams of Derby.

    A brief initial walkover was sufficient to reveal that parts of the

    station canopy were in an appalling state. The platforms

    beneath the fenced-off areas of the canopy were strewn with

    rivet heads from failed fixings and the bays at the southern end

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    Figure 2. Aerial view of station canopies

    Figure 3. South end of canopy before restoration

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    were in a particularly parlous condition; many of the diagonal

    web flats in the lattice beams had been lost completely to

    corrosion. The proximity of the railway and delicate condition

    of the fabric meant that health and safety considerations were of

    all the more concern. Following discussions with rail operator

    Nexus, details of working methods and emergency procedures

    were compiled into a report and this was distributed to all active

    parties before any surveys were undertaken. A day-long on-site

    review of the project was also undertaken prior to work, at

    which all staff involved in the project were present, as well as a

    director independent from the project team.

    It was clear from initial site visits that detailed discussion

    would need to be held during the survey with regard to the

    extent of replacement of fabric, because of the extent of

    corrosion. The conservation philosophy of minimum inter-

    vention demands that the conservation engineer understands

    what is and is not structurally acceptable: what is a necessary

    intervention to restore structural performance and what isover-zealous and destructive to the listed fabric. In order to

    establish this, prior to survey an assessment of the required

    capacity of critical elements of the fabric was made, in

    particular the wrought iron arches and the long-span lattice

    trusses. This was done using hand calculation methods. It

    provided a basis on which residual section thickness could be

    measured for each element. For example, the critical section

    thickness of back-to-back angles for end bays of arch trusses

    was conservatively taken as a modest 4 mm, compared with

    the J in (6.3 mm) original thickness. This meant that

    elements with reasonable levels of section loss could be

    accepted in certain locations.

    The survey was undertaken over a continuous 2-week period

    in April 2009. Two members of staff were engaged on site,

    lodging locally, with two mobile access platforms and machineoperators at their disposal to provide fingertip access to all

    areas. Site visits from the project director and the company

    materials specialist helped to calibrate the findings of the work

    by comparing the notes being made by each surveyor and

    providing independent review.

    5. DefectsThe station is located about 800 m from the North Sea and, as

    the roof had failed in many places and the ironwork paint

    system was almost non-existent in places through failure, it was

    inevitable that very high levels of corrosion were found

    throughout the structure. This was far more serious at theexposed northern and southern ends, where the ironwork was

    unprotected by asbestos-cement sheeting or glazing. The

    defects were categorised and listed in the final report using,

    as an appendix, a photographic gazetteer. The following

    subsections describe the most common types of defect (also

    seeFigures 58).

    5.1 Lattice trusses

    & Heavy corrosion and reduced section of top and bottom

    chords to lattice trusses. Corrosion in the bottom chord

    with very serious delamination of the wrought plates was

    common, because the double angles, facing upwards,

    trapped the rain in pockets.

    & Heavy corrosion and reduced section or failure of lattice

    truss web members. Complete loss of section at the point at

    which they met the bottom chord was common at the south

    end of the canopy, the iron flat necking to failure.

    & Dimensional expansion of lattice truss bottom chords,

    sufficient to result in the splitting of plates from angles and

    a consequent failure of rivets.

    Figure 4. Survey inspection in April 2009

    Figure 5. Typical column fracture

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    & Cracking through the section of the filigree cast-iron

    brackets below the ends of the lattice trusses, both in

    purely decorative parts and the thicker, structural angles,

    circles and swags, generally as a result of expansion of

    adjacent corroding components.

    5.2 Arch trusses

    & Heavy corrosion and reduced angle sections in the arch

    trusses, in particular on the top chord.

    & Delamination of the drilled cheese plate packer at the

    connection to lattice trusses, which was drilled to sit over

    the top of the rivet heads.

    & Delamination of the various gussets and plates sandwiched

    between the chord angles.

    5.3 Columns

    & Horizontal cracking through the columns immediately

    above the level of the square impost (plinth or simple

    capital) of the casting, in many cases completely splitting

    the top from the bottom (see Figure 5). The extent of thiscracking was not immediately apparent from the early

    ground-level walkover inspections, but it quickly became

    clear from fingertip work that this defect extended to almost

    all columns in the canopy. It was a very serious defect to

    overcome in order to complete a structurally acceptable

    solution in the restoration.

    & Cracking through the root of the seating corbel to the arch

    trusses, in which the corbels had been jacked away by

    corrosion.

    & Cracking at lower levels in the columns, for example a

    circumferential crack, or one clearly due to impact, of which

    there were only a few cases.

    The diagnosis of the cause of the column cracking was almost

    certainly the jacking of the very heavy corrosion deposits on

    the underside of the arch trusses where they rested on the cast

    corbel beside the impost, forcing the upper section away from

    the lower through the bolted connections between assemblies.

    This may well have been exacerbated towards the ends of

    the canopy by longitudinal thermal movement, racking the

    columns back and forth over successive seasons.

    The cracks in the columns at impost level were widespread,

    present in almost every column inspected. They posed a

    considerable threat to the fabric, as total replacement wouldresult in huge trauma to the listed structure. They also

    threatened the viability of the project itself, as the cost of total

    replacement would have been prohibitive, as it was unfunded.

    Figure 6. Trial works in progress

    Figure 7. Disintegration of the cast-iron brackets

    Figure 8. Delamination of the flanges of the lattice trusses

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    A risk-based approach was adopted for the inspection offixings. There are no conclusive, reliable methods for assessing

    the integrity of bolts and rivets in a structure that exhibits such

    extreme levels of corrosion. Therefore the function of each set

    of fixings, their location and type were all taken into account in

    examining the need for replacement.

    Corrosion of bolt fixings was clearly very advanced in places.

    Where these passed through the columns it was sometimes

    possible to see the shank by looking down from above the

    guttering; these had in many places wasted away to a fraction

    of original thickness, or to nothing. It was therefore planned to

    replace all key bolted connections into or through the columnsregardless of whether the elements would be dismantled or not.

    The exception was the connection between arch and lattice

    trusses, which having a six-bolt connection had a high

    degree of redundancy and in general showed relatively little

    sign of corrosion.

    Rivets had been falling from the underside of the lattice trusses

    over a large area of the canopy, and rivet-heads littered the

    platform. As ironwork in the end bays of the station had to be

    disassembled and reconstructed, these would be replaced in

    entirety. Towards the centre, where rivets were found to have

    greater integrity, it was necessary to find a philosophy that

    respected the original fabric while ensuring structural capacity,

    and one in every three was replaced using bolt equivalents.

    The survey report and accompanying drawings (see Figures 9

    and10) were accompanied by a report outlining the philosophy

    of repair. Together, these documents were submitted for listed

    building consent, and their approval was part of the deliberate

    effort to achieve as great a body of approved works as possible

    before starting works on site.

    6. Conservation philosophy

    6.1 Trial worksModern conservation philosophy in Britain goes back to the

    origin of the UKs Society for the Protection of Ancient Buildings

    in 1877 and is based on an assumption of minimum intervention.

    This is widely accepted across the world, as conservation thought

    has developed through the Treaties of Athens and Venice and,

    later in the twentieth century, the Burra Charter (ICOMOS,

    1979). In an overseas setting this can still mean the environmental

    threats such as seismic activity and extreme storms can demand

    structural intervention to offset the risk to fabric. However, the

    UK does not suffer from significant seismic activity and so this

    threat does not impose an obligation on the conservation engineer

    to intervene to enhance seismic resistance.

    The temptation for the engineering professional in handling

    corroded ironwork is to adopt high levels of replacement for

    what are thought to be practical reasons, for example

    substituting a complete angle section when only a relatively

    small length is seriously corroded. This was indeed the

    approach presumed in a document written just before the

    project received funding, where it was said that the system (of

    ironwork construction) does not favour selective repair as inmasonry or timber construction (North of England Civic

    Trust, 2007); in other words, a more extensive reconstruction

    would be necessary. However, at Tynemouth this approach

    would have resulted in very significant loss of original fabric.

    In many places, such as on the corners of arch trusses touching

    the gutters, significant corrosion had occurred, but only to

    quite limited lengths of each angle component. The suitability

    of conducting local, limited repairs needed to be examined and

    proved.

    A trial project was undertaken at the same time as the survey

    work, funded by English Heritage. This was undertaken on acorner bay on the south end and was intended to address the

    philosophy of repair. It used a number of alternative solutions

    and techniques, as follows.

    Figure 9. Structural actions on columns

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    & The badly corroded web flats were cut back and repaired by

    both fire-welding wrought iron flats and electric fusion-

    welding mild steel flats.

    & The rivets were replaced by both hot-riveted mild steel

    equivalents and dome-headed, hexagonal, slotted bolts.

    & Equivalent modern, metric, mild steel angle sections were

    used to substitute for original nineteenth century imperial

    wrought iron sizes.

    & A repair of the cracked column section was trialled, using

    an internal sleeve bonded in place with low-viscosity resin.

    The works were inspected by the project team and English

    Heritage on completion. The trial project was completed at

    a cost of around 30 000. It was a very valuable exercise,

    enabling techniques to be proposed, trialled and approved in

    advance of the project, providing cost indicators, reducing cost

    risk and assisting specification. The conclusions of the trial

    works were taken forward in a report that proposed the forms

    of repair (Jacques and Miller, 2009). This sought to adhere

    closely to established UK conservation practice (BSI, 1998,

    2014;English Heritage, 2008).

    6.2 Philosophy of column repairs

    The issue of column fracture was a great concern. Almost all

    the columns exhibited this defect. In effect the tops which

    connected to the lattice and arch trusses were separate from

    the main shafts below. Regrettably, also, the column repair

    that had been undertaken during the trial works could not be

    used for columns that acted as rainwater down-pipes, as the

    internal sleeve would block the flow of water. So even at the

    end of the survey and trial works there was still no universal

    solution for repair of the fractured columns.

    Both the structural behaviour and the conservation philosophy

    for repair of these elements were examined in detail.Engineering practice might have been to dictate total replace-

    ment of all such highly fractured column components, where

    the defect runs right through the stressed section. However,

    there was a strong argument not to replace the columns: the

    loss of original fabric would be considerable and dismantling

    of the whole structure would cause considerable trauma to the

    frame and risk of geometric misfit on reassembly.

    The key to solving this conflict was a careful consideration of

    the structural actions and load paths. The various actions on

    the roof structure were examined and are shown diagrammi-

    cally inFigure 9. The possibility of separation of the columnand the way in which tying action and integrity might be

    maintained were considered. The problem was resolved by

    careful consideration of the tying, ensuring also that the parts

    Gridline A Gridline B

    1in 3 rivets replaced in top chord

    Gridline B-1

    Gridline B-2

    Gridline B-3

    West elevation

    West elevation

    West elevation

    West elevation

    West elevation1211

    10

    10 10

    10

    1112

    13 13

    West elevation

    Gridline 3 south elevation

    Live railway

    To be reconstructedA B C D

    7 7

    5

    5

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    7

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    7 7

    55

    4

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    B-1 B-2 B-3

    3 4

    1500

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    3 4

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    Figure 10. Truss elevation showing extent of repairs

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    could be positively located; this placed a greater emphasis onthe integrity of the cast-iron filigree brackets, which provided a

    load path for tying action, bolted to both the ironwork above

    and the column shaft below.

    The issues relating to the columns were considered such an

    important matter that a separate report was issued to English

    Heritage, outlining the concerns and solution.

    6.3 Ironwork materials

    The conservation philosophy discussed material choice.

    Wrought iron is no longer manufactured in structural

    quantities anywhere in the world, and the use of recycled

    material would have been inappropriate for the project. The

    precedent for mild steel replacement was examined and this

    was specified for repairs, either in full replacement or, as in

    many areas, where wrought iron was cut out locally and new

    material fusion-welded in place.

    It was clear that the cast-iron filigree brackets supporting the

    lattice trusses had fractured in various tensile failures. This was

    particularly important when considering their role in main-

    taining continuity around the column fractures. A higher

    tensile capacity was required in new elements and spheroidal

    graphite iron (SGI) was chosen as a substitute for grey castiron.

    After many years of abortive schemes, the project itself was

    finally kick-started by the risks posed by bolt failure, which

    would have caused catastrophic failure of ironwork over-

    hanging the railway. The bolt specification was critical. There

    was little debate over the proposed use of stainless steel

    replacement bolts. Hard nylon electrical isolation inserts were

    used to prevent bi-metallic corrosion. This meant that bolt

    sizes were 2 mm smaller than original, to fit inside the inserts,

    which was compensated for by use of a higher bolt grade. Rivet

    replacements were dome-headed bolts, not hot-riveted mildsteel studs.

    7. Specification

    The standard materials and workmanship specification used

    on building works in the UK is in the National Building

    Specification (NBS). In the case of the ironwork restoration,

    virtually no part of the NBS was relevant and a new

    specification section was written for the ironworks.

    Elevation drawings for the repairs on each grid line were

    produced from the survey, on which competitive tenders were

    based. The value of a good written specification is that it can beused to control both work that appears on the drawings and

    other unforeseen repairs, and this is particularly important on

    an historic restoration.

    Key features of the works specification are

    & the requirement for a photographic record prior to works

    & a clause defining the experience of the ironwork subcon-

    tractors on historic fabric

    & a clause requiring the names and brief experience of all

    operatives working on the project to be submitted

    & details of how the careful dismantling of the canopy should

    be undertaken

    & requirements for a full dimensional survey of the structure

    prior to dismantling

    & a diagram defining which areas may be dismantled and

    which may not, which had been previously agreed withEnglish Heritage through listed building consent

    & requirements for marking and recording dismantled com-

    ponents

    & precise details of bolt substitutions and grades

    & precise details of mild steel section sizes for substitution of

    imperial with metric sizes, which, again, had previously

    been agreed through listed building consent

    & a clause defining which direction rivet substitutes should

    face.

    The areas that could or should be dismantled were carefully

    defined, as the greater the area of canopy taken down, the

    greater would be the trauma on the fabric and potential loss of

    the original. A diagram binding the contractor to certain limits

    and areas was included in documentation. The bills of

    quantities required the contractor to establish rates for most

    types of repair, including the re-casting of iron elements,

    showing the mould and unit prices separately. In addition to

    other contractual matters, there were clauses describing the

    risk of working close to the live overhead lines of the railway

    and the interface with rail authorities.

    The corrosion protection comprised a zinc-rich epoxy primer

    designed for use after wet blasting, zinc-rich epoxy undercoats

    and an acrylic urethane top coat.

    8. Site works

    The project was advertised through the OJEU (Official Journal

    of the European Union) process. Works started in March 2011

    and were completed in April 2012 (see Figures 1114). The

    final contract valuation was 3.9 million. Main contractor for

    the works was Mansell Construction Services Limited from

    Gateshead and their chosen ironwork repair subcontractor was

    Eura Conservation Limited from Telford.

    The dismantling proceeded well. Components were marked

    with two tags, so that if one marker was lost, another wouldremain attached. The contractor opted to dismantle to the full

    extent of permitted areas, and two additional grids were also

    agreed in conjunction with English Heritage.

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    The cast-iron filigree brackets had been carefully inspected

    twice to specify the number of replacements. However, as

    disassembly proceeded, many others simply fell to pieces as

    either the rapid change of stress caused fracture or the release

    of load revealed pre-existing defects. This led to a higher level

    of replacement, with 49 new brackets out of a total of 86 within

    the works area.

    The cleaning of paint from ironwork was achieved using a ultra-

    high-pressure system, with water jetted at about 32 000 psi

    (220.6 N/mm2

    ) through a spinning head. No blast mediumwas used. Water usage was relatively low, about 1015 l/min

    depending on the nozzle size.

    The contractor reported that one column visibly moved on

    removal of the interconnecting ironwork as the foundation

    settled sideways, and this led to a concern that the latticework

    would no longer fit onto the columns on re-erection.

    Thankfully this proved unfounded and reassembly proceeded

    remarkably smoothly.

    It had not been possible to inspect the cast-iron gutters in detail

    during the survey phase. These were deep channels laid flatbetween the down-pipe columns, and a fall for rainwater

    appeared to have been created by compacting burnt coal ash in

    the bottom of the units. This sulfurous material had both

    Figure 11. Reconstruction of lattice truss in works

    Figure 12. Fettling of new SGI filigree brackets

    Figure 13. Corrosion of the gutter resulting from sulfurous

    deposits

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    caused and masked the extent of corrosion in the base

    (Figure 13), and a significant number of sections had to be

    either re-cast or repairs made when they were dismantled and

    inspected in the workshop.

    9. Conclusions

    This was a successful project, delivered on time, to budget, with

    good working arrangements between parties and above all

    with appropriate levels of historic intervention.

    Key to the success of the project were the following factors.

    & The processes gave time for the effect of each causal activity

    to be examined: for example, the detailed survey allowed a

    suite of repairs to be proposed and critiqued, rather than

    trying to work details out on site without prior approval.

    & The trial works allowed experimentation in types of repairin advance of the works, agreement between parties and

    better establishing of costs for the works.

    & The survey was undertaken in sufficient detail to allow

    every ironwork repair to be scheduled, even if some changes

    were made during the site works.

    & A clear conservation philosophy was put forward at the time

    of the application under UK heritage protection legislation.

    & A thorough engineering review was undertaken on site,

    involving staff with the highest levels of historic and

    materials experience, at an early stage in the project.

    & A pro-active contractor was chosen for the project, and the

    client and contractor were willing to talk openly about costconcerns and programme issues.

    & The contractor chose an ironwork subcontractor with good

    experience in historic repair; this was due in part to the

    wording of the specification and emphasis on quality at

    tender interview.

    The result is a significant ironwork restoration project where

    the repairs are distinct to the trained eye, while the canopy

    retains a unity as a whole (Figure 15). Defects are still visible,

    for example, some brackets remain cracked and many

    wrought iron sections are thinned by corrosion. However,the overall level of intervention is commensurate with the

    structural performance of the fabric: a balance has been

    achieved.

    Throughout the site phase, the team was mindful of the

    preceding many decades of project failure, through lack of

    community agreement and lack of funding. There was a very

    strong will to conclude the work successfully. The result is an

    ironwork restoration that follows contemporary conservation

    philosophy and in which everyone involved has taken

    considerable pride.

    REFERENCES

    BSI (1998) BS 7913:1998: Guide to the principles of the

    conservation of historic buildings. BSI, London, UK.

    BSI (2014) BS 7913:2013: Guide to the conservation of historic

    buildings. BSI, London, UK.

    English Heritage (2008) Conservation Principles, Policies and

    Guidance. English Heritage, London, UK.

    ICOMOS (International Council on Monuments and Sites) (1979)

    The Burra Charter, 1979 edition and subsequent revisions.

    ICOMOS, Burwood, Victoria, Australia.

    Jacques S and Miller JD (2009) Tynemouth Station Newcastle,

    Conservation Philosophy for Structural Repairs. Gifford,now Ramboll UK Ltd, London, UK.

    Leyton A(undated)The Opening of the First Newcastle to North

    Shields Railway. Archive of the Friends of Tynemouth

    Figure 14. Reassembly in progress in September 2011

    Figure 15. South end of the restored canopy

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    Station, by kind permission of Ylana First (unpublishedarticle).

    North East Civic Trust (2001) Tynemouth Station Conservation

    Strategy. North East Civic Trust, Newcastle upon Tyne,

    UK.

    North of England Civic Trust (2007) Tynemouth Station OptionsAppraisal, Final Report. North of England Civic Trust,

    Newcastle upon Tyne, UK.

    Wells JA (1989) The Blyth and Tyne Branch Volume II 1874

    1989. Northumberland County Library, UK.

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