Covenants, Easements & Wayleaves: Transport asset interface register (Part 2)

We now delve deeper into evolution of railway infrastructure knowledge that we started in Part 1 of this series. We look at some more recent examples of how underground railway infrastructure interfaces with its environment in London, and some international examples of railway-based infrastructure interfaces with its environment. We also consider the development of a practical framework for the identification and clarification of how transport infrastructure and its environment are interconnected and interdependent, that can be used globally.

long-term effect on the urban environment

Today, extensions to Tube lines, and new lines such as Crossrail, have further increased the presence, property, and protection interfaces with private property. In part this is due to the increased size of the tunnels – 6 m+ for main line gauge trains, compared to the earlier Tube railways’ tunnel diameters of about 4 m. Moreover, since the construction of the Jubilee Line Extension, in the 1990s, an emergency walkway within the tunnel has been required. The HS2 tunnel diameter will be even larger.

Additionally, there is the increasing need for related railway infrastructure – station boxes, connecting passages, ventilation, and emergency intervention shafts. All of these increase the area of sub-soil and surface area required for the operation of the underground railway.

Picking up the conversation with Dr Nathan Darroch, railway infrastructure expert, we take a deeper dive into infrastructure. He had described that in addition to the increasing size of railway infrastructure, taller and deeper buildings have been constructed, with this trend increasing in the decades to come. To mitigate risk of conflicts between building foundations (piles) and tube railway tunnels, the 1960s legislation for the construction of the Victoria line extension from Victoria to Brixton contained provisions for London Transport to acquire the additional land and subsoil it required to protect its physical infrastructure. This was in addition to the land and subsoil it required for that physical infrastructure. The principle of acquiring additional land and sub-soil to protect the railway infrastructure was duly followed by the Jubilee Line Extension and Crossrail 1. Should an interfacing landowner wish to use the subsoil under their land owned by London Underground or another railway entity, they must first gain the permission of the railway owner and enter into a legal agreement, such as a lease or a licence.

However, due to legal challenges by urban landowners who would have had to relinquish their ownership of the subsoil when railways were proposed, the legal ownership of the subsoil is not always London Underground’s or TfL’s, Darroch cautioned:

“It is in fact a patch work along the lines of route of the post 1960s Tube railways. Indeed, whilst London Transport had the powers to take the subsoil for the construction of the railway, in many cases only an easement was taken, as with the earlier Tube railways. In these instances, London Underground and TfL do not have any legal right to stop the use of the subsoil adjacent to the tunnels, except through a court injunction where there is a serious and apparent risk during construction works”.

The property annulus must also not be confused with the Civil Engineering Zone of Influence, which is an advisory based on engineering considerations to protect underground infrastructure from the adverse effects of underground construction. This Zone of Influence, therefore, is an engineering indicator of where London Underground wishes to consult with a developer to ensure that their work does not adversely affect the safe presence and operation of the railway. However, it is again not legally enforceable, even though it applies across the whole of the network.

The diagram above represents a simplified interpretation of the evolution of the interfaces between tube railways and their environment in London, and the effects and affects of one on the other. As can be seen from the diagram, where tube tunnels are present under low level buildings, there is minimal effect on the foundation design of the building. As construction technology has advanced, buildings have become taller and where there is physical, property, and protection scope at ground and below ground levels, the foundations are designed to be located around the tunnels. Darroch explains. “With the introduction of the property ownership of the subsoil, the influence of the railway increases, until it reaches a point where the physical and property interfaces of the railway prohibit the use of the subsoil under the land of urban landowners”.

Darroch presented a post-1920s example of such proscriptive effects on the development of urban land due to the presence of tube railway infrastructure at South Wimbledon on the Northern line. In that instance, a 1920s constructed escalator shaft prohibits the development of land behind The Grove pub, on the corner of Merton High Street and Morden Road, London, UK. “It has never been developed, though I do remember receiving a few proposals to London Underground for it to be so”, Darroch says.

Due to the escalator shaft from the ground floor level of the station down to the two station tunnels beneath, however, there is basically nowhere to put the foundations for a new building. And there is a risk of adding too much weight to the shaft causing it to distort. That would cause problems with the operation of the escalators, which have very fine tolerances for movement. Since the station was built, therefore, the land behind the pub has always been empty.

Underground railway presence affecting its surface environment

The photograph below shows an effect of the Crossrail tunnels on its environment surface. This new development by the River Thames in Woolwich is clearly widely spaced, not only to accommodate urban open space, but because of the presence of the 6m diameter Crossrail tunnels which are located directly below and between the new buildings. The presence of the tunnels, even before the construction of the new development commenced, required the new development to be designed and built to accommodate not only the physical presence of the railway infrastructure, but also its property interfaces in the form of the annulus, rights, and responsibilities of Crossrail and the buildings’ developer to ensure the safe continued presence and operation of the tunnels and its environment. Darroch commented that “whilst beneficial for the provision of public open space in suburban Woolwich, south east London, in central densely urbanised areas, such as Londons’ Zone 1, this effect could well limit future densification of urban space”.

British Library development

Another example is the British Library on Euston Road. The current Library building was built in the 1980s, and was designed to accommodate the existing 1900s Northern line and 1960s Victoria line Tube tunnels beneath the site. Moreover the construction works had to accommodate the adjacent, 1940s reconstructed sub-surface Metropolitan line, under Euston Road. (The Metropolitan line station was constructed in the late 1930s to replace the original station further east. Some amendment to the existing 1860s tunnels was undertaken to accommodate the new station site). This accommodation was achieved by cantilevering the building over the tunnels with deeper basements and under-reamed piles between Euston Road and the side of the Victoria line tunnels.

Whilst the above image represents the physical nature of the building and the interfacing underground railway infrastructure, it is also worth considering the property interfaces, identified in the image below.

The area shaded green and labelled F represents the land and subsoil ownership of the British Library; areas shaded red and labelled A represent the subsoil ownership of London Underground for the presence of its infrastructure; and the area shaded yellow, labelled G, represents land, airspace, and subsoil forming Euston Road.

I asked Darroch how these property interfaces came about and what they meant. He explained that “the land upon which the library was located currently used to be owned by the British Transport Commission, owner of the national and London railway network until 1962”. He stated that until the sale of the land for the construction of the library, British Rail had retained ownership of the land, but that the tube tunnels were present through an easement only. “As such, the sale of the land saw the transfer of ownership of the subsoil for the Northern and Victoria line tunnels to London Underground, whilst the remainder was sold to the British Library. Within the sale were imposed covenants (that is, legal requirements) for the owner of the land, and its successors, to consult with London Transport, and its successors, for any proposals of construction, demolition, and alteration to buildings”.

Darroch went on to explain that the subsoil under the Euston Road, “belongs to London Underground as part of the taking of the subsoil of the road for the construction of the 1940s new Kings Cross station”. As can be seen from the red shaded area in the image, however, the ownership of the subsoil under the road, stopped short of the foundations of the road, though London Transport and its successors still had a responsibility to provide a right of support to the roadway above. With regard to the yellow shaded land, subsoil, and airspace forming Euston Road, he explained that he had not been able to determine the actual property ownerships, rights and responsibilities due to the historical occurrences of road widening and the subsequent complexities of land acquisition.

The British Library has outgrown this building, however, and plans are well underway to redevelop the site. Complicating the design, of course, is the presence of these same tunnels. Not just the new Library development, but demolition and re construction on the site will require the developer to submit and gain written permission of London Underground due to the covenants imposed on the land. These covenants require London Underground to provide explicit consent of the proposed designs and methods of construction before work can be undertaken.

Japanese developer Mitsui Fudosan signed a deal with the library to develop the 700,000 ft² scheme in 2019, whilst Rogers Stirk Harbour + Partners was awarded the architectural design contract two years previously. However, design has been delayed by plans to build a new station underneath the plot for the proposed Crossrail 2 line. But in July 2020 TfL reached an agreement with the British Library to resolve this issue.

Notwithstanding the November 2020 Government announcement to defer the design of the Crossrail 2 line in view of pandemic and other economic priorities, the work of refreshing the 2015 safeguarding directions to protect the Crossrail 2 route from future development will continue. This will ensure that this new railway infrastructure can still be constructed whence a long-term sustainable funding model is in place. Thus demonstrating how there is an essential need to understand how urban underground railway infrastructure is not only physical but has many and complicated property and protection considerations, which affect and are affected by their environment and historical events.

international infrastructure asset examples

The principles of having to design around and accommodate underground railway infrastructure is not new, nor is it exclusive to London – it is a global occurrence. During Darroch’s research, he undertook international consultations with various metro organisations across the world to determine whether they had similar occurrences of the interfaces between their infrastructure and its environment as has occurred in London. “I found that cities across the world had nearly identical issues with regard to the management of the interfaces between their metro infrastructure and its environment”, he stated. “In fact, all metro organisations had teams specifically dealing with the management of the interfaces and how they did this was also similar, whether they work in the UK, Europe, Asia, or North and South America”.

The images below, for example, are taken from the Hong Kong Metro website MTR, 2014 [https://www.mtr.com.hk/en/corporate/operations/protection_effects.html] and present some examples of how urban development nearby can adversely affect underground infrastructure.

The following table presents some of the works undertaken for urban re-construction which may affect or be affected by the presence of underground railway infrastructure, taken from Darroch, 2019. He explained that it is just as important to consider the under ground effects of urban development (the first two left hand columns), as it is for urban development in the air space above railway-based systems (the right column). Especially where there is railway in open cutting, as the Underground is more open to the sky than below ground.

Underground Infrastructure	Effects of Urban Development	Urban Development in Air Space above Railway Infrastructure
Underground tunnels	Underground installations	Viaducts, overhead power cables and at-grade structures
Pile installation	Direct damage	Construction work
Shaft excavation	Excessive displacement	High level works
Diaphragm wall	Excessive vibration	Material storage
Bulk excavation	Excessive stress	Vehicle movement / parking
Blasting		Objects falling onto tracks
Coring / drilling		Fire and flood hazards
Grouting		Structural damage due to direct vehicle / ship collision etc.

As Darroch explains, however, the interfaces of metro infrastructure and its environment across the world are not just physical. He states that even though the physical aspects are the most common consideration, and his research to date supports this argument, it is essential for transport and urban planners, legal professionals, asset managers, engineers, etc, to have a holistic view of the collective physical and property and protection occurrences of the metro infrastructure and its environment.

Times Square Subway Station, New York City

London Reconnections has covered the many similarities between the development of London’s Underground and New York City’s subway. Due to various factors, Manhattan skyscraper development took off in the 1920s, and which were supported by the rapidly growing subway network.

As can be expected, this created many subway interfaces with the surrounding urban fabric, under and within public roads, and under and within privately owned buildings. One excellent example of the latter is the New York Times building at One Times Square, bounded by 42nd and 43rd Streets, Broadway, and Seventh Avenue. With 25 storeys above ground and four storeys below ground, its basement wraps around the 1900s constructed, four track, Times Square station. The four tracks provide two inner tracks for express services and two outer tracks for local services.

The incorporation of the subway station within the Times building, which were built at the same time, required close and iterative design and engineering agreement between the developer of the building and the Subway company. This ensured that the proposed designs, methods of construction, allocation of property, and asset management, for the lifespan of the infrastructure, was assured. Note how the basement levels, within the image above, which housed the newspaper printing presses, surround the subway station. The 1904 building and subway station are both still in use today, and with the New Year’s Countdown ball still dropping down on the roof of the Times Building’s roof, although the New York Times company has decamped to a larger, more modern building.

The outcome of the construction of the Times Building and the Subway sharing the same land footprint and infrastructure required specific details of the ownership, rights, and responsibilities for the infrastructure. The image below therefore shows the interpretation of the property and asset maintenance responsibilities for the interfacing stakeholders, where the following shading represents:

• Green – New York Times
• Red – New York Subway
• Purple – local road authority

The examples of the interfaces in this article and its predecessor are not exclusive to underground railways, however. They also occur where there are surface railway-based infrastructure and its environment. For example, the two following images show the presence and property interfaces of a tramway passing through a building in Den Haag, Netherlands. The building has been designed to wrap around the tramway. The principles of the tramway having presence, property, and protection interfaces with its environment are the same as urban underground metro infrastructure, it is only that in instances such as this, they are on the surface.

Ad-hoc vs scientific approaches to asset data management

Given the complex nature of the urban underground railways and other railway-based systems and their environment, Darroch argues that it is absolutely essential to current and future urban and transport planning to have holistic comprehension of how those transport networks and their environment are interconnected and interdependent.

Darroch’s investigative analysis was multi-layered:

The interfaces of transport infrastructure and its environment are not quantitative, they are not 2+2=4. They are mostly qualitative and require qualitative approaches to understanding (consideration of archived data including engineering reports, legal documents, as built drawings, proposal drawings, legislation, interviews with stakeholders) and the piecing together of different philosophies and reasonings over the whole life of an asset. Where is the evidence, could it actually be part of a larger sum with missing information. The latter was and still is my experience, and the more I discuss infrastructure interfaces with practitioners worldwide, they also identify with that thought.

In his professional work, he used 53 different archives and hundreds of different types of primary (first hand) and secondary (later evidence) data, held by LU/TfL, the Greater London Assembly, utility companies, etc.

Major cities are subject to an ever increasing complexity of surface and subsurface assets such as pipes, cables, piles, foundations, tunnels etc. Thus it is clear from the many examples presented here (and there are thousands more around the world) that a much more comprehensive approach to railway asset management was needed. Through Darroch’s London professional and academic experience and consultation with international metro systems, he realised that there did not appear to be the required knowledge and tools then available to effectively consider the multi-disciplinary aspects of urban interface management.

It was apparent that there was a heavy dependence on civil engineers to undertake engineering, legal, and property work, where developers were proposing urban redevelopment or even planning new infrastructure. Those engineers would of course consult their colleagues in other teams and departments, but how did they know when to do that? How did they know what to ask colleagues about? Did they consider what, how, when, where, and why the interfaces occurred? Or did they just focus on the contemporary occurrence? More importantly, it was apparent that there was just not the time or money available to undertake such detailed analysis of the interfaces, despite its potential to save organisations time and money in the short and long terms.

Essentially, I was left asking questions like ‘how do you know where your infrastructure interfaces with other peoples assets? How do you know that you are maintaining, managing, or operating infrastructure that is yours? Or does the asset you are spending money on actually belong to your organisation or does it belong to someone else and is it there responsibility?

From my professional experience, I undertook over 2,000 analyses of occurrences of the interfaces of London’s transport infrastructure and its environment. Let me just say I was surprised at the lack of available evidence-based data for me to provide detailed answers to asset managers. The information I did find was in many and different formats and archives, and it took a long time to gather the pertinent data and reach appropriate decisions that enabled business decision making.

Many of those flaws come from a lack of knowledge of the interfaces caused by many different factors, including but not limited to:

• changes in organisational archiving and recording policy,
• changes to asset ownership and loss of documentation,
• methods of recording and archiving data (eg using paper or storing data with odd titles etc),
• government policy, causing massive change to infrastructure ownership, rights, and responsibilities (eg, the re-vesting of parts of LU and British Rail, where agreements were not completed),
• lack of sharing of data within an organisation or with its interfacing stakeholders,
• accessibility to data, required by multi-disciplinary professionals across an organisation or its interfacing stakeholders (eg 3D modelling is good for a project, but not for someone who is not trained in the use of 3D modelling software),
• professionals not understanding how their roles affect and are affected by other disciplines within an organisation or interfacing stakeholders,
• loss of people with the knowledge required to assist effective decision making.

These issues were identified among professionals and in current academic literature describing the development of Building Information Management, and 3D and 4D modelling, which are intended to enable more effective asset management. “Asset management is data intensive”, Darroch explained, “however, that data needs to have its provenance checked, be evidence-based, and be multi-disciplinary. It is not sufficient nor cost effective to develop asset management processes and strategies for existing infrastructure, which can be up to 160 years old, that are based on inaccurate data. But that is what will occur if there are not more scientific approaches to analysis of the interfaces of transport infrastructure and its environment; training of staff in organisations; and the sharing of knowledge between interfacing stakeholders, and policy makers, globally”.

Darroch stated that this does not mean that urban metro infrastructure and its environment are not safe. The risk is considered to be as low as reasonably possible, but it could be better. “There is an identified need, highlighted by infrastructure interface managers from across the world, for more effective methods of understanding how their infrastructure affects and is affected by its environment. Those infrastructure and asset managers are doing their best with what they have, but this is costing fare and taxpayers money, unnecessarily”.

For example, utilities like gas and fuel pipelines, power cables, and water/sewage tunnels, if breached near railway infrastructure, can cause significant damage and are potentially injurious or deadly in worst cases. Fortunately, the AIR processes are highly applicable to utilities and indeed are intended to be used where they interface with a railway environment.

Wait – don’t GIS systems include these interfaces?

There are many reasons why utilities, boroughs, and organisations don’t share their data, including:

• they are not actually sure where it is in relation to its environment, so they request people proposing works in the urban environment to contact them first;
• there is a lack of willingness or investment in developing new forms of analysis and comprehension of how urban infrastructure interfaces with its environment;
• the lack of knowledge of how or why analysis should be undertaken;
• or just pride.

To counteract these tendencies, the UK Government had formed the Geospatial Commission in 2018 to coordinate a GIS strategy across the land, to map the occurrences of physical infrastructure interfacing with its environment. The commission consists of six partner bodies (the ‘Geo6’):

1. British Geological Survey
2. Coal Authority
3. UK Hydrographic Office
4. HM Land Registry
5. Ordnance Survey
6. the Valuation Office Agency.

Every year, the Commission estimates that accidental strikes on underground pipes and cables cost the economy an estimated £1.2 billion, and put lives at risk. However, the Commission’s primary focus is street works, and not utilities or railway infrastructure. Nevertheless, they have completed two regional pilot schemes to bring existing underground asset data together.

It is important to note that this data does not provide asset ownership, rights, and responsibilities information, nor details on the processes of asset protection (such as legal agreements, etc). So whilst this is a noble effort, it literally only scratches the surface of asset management for transport purposes.

With millions of data points in a city, however, their effort will take decades to provide a comprehensive database for a major city like London.

Something better was needed

Alas, ad hoc does not cut it any more. Property, money, and most importantly, lives are at stake. Most underground metro organisations globally, have teams which amongst other things:

• provide plans showing locations of their infrastructure to ensure interfacing developers or utilities owners know where the metro infrastructure is located;
• consult on urban planning near that metro infrastructure;
• consult with interfacing developers on their proposals, from design to completion;
• consult with utilities companies to ensure their works do not adversely affect the physical railway infrastructure;
• advise hauliers of safe routes through London, to avoid passing overweight restricted structures;
• consult on and clarify property interfaces with interfacing landowners, utility companies, and other railway operators.

Whilst metro organisations have the same objectives to ensure the safe presence and operation of their infrastructure, they are likely to approach management of the interfaces in different ways, not only between countries or metro systems, but within teams and departments within an organisation.

To address the needs and requirements of asset managers, globally, Darroch developed processes of multi-disciplinary analysis, evidence-based data gathering and recording, validation of the data, and publication of the data in a simple to access, easy to use format. “this will enable a common standardised approach to analysis, based on scientific principles”, Darroch explained. “Through the application of processes such as these, more effective Building Information Modelling (BIM), asset data management, 3D and 4D modelling, and management of the interfaces between existing metro infrastructure and its environment can be achieved. These processes are designed to be employed by different interested parties in the urban environment”.

The evolution of a new discipline

As our conversation continued, Darroch relayed his interest in the effects of transport on its environment, starting over 30 years ago with his interest in transport history. He has a long history in public transport: he drove a London bus for two years, then a Croydon tram for a further five. Whilst at London Underground, he undertook the part-time University of York’s Transport History and Railway Studies program. This led to him undertaking his part-time MA in Railway Studies, with the dissertation focusing on the development of Tube railways in London from legal, geographical, and civil engineering perspectives.

Through these experiences, he identified the gap in comprehension of how railways affect, and are affected, by their environment, and the lack of knowledge and understanding of them within academia and at transport agencies. To assist the further consideration of these effects and affects, Darroch went on to do his part-time PhD in Transport Studies within the Centre for Transport Research at the University of Aberdeen. Nonetheless, his day job at TfL also saw him evolve to take on roles such as Systems Integration Coordinator for the Bakerloo Line Extension (BLE) project. There he applied his academic and professional skills and knowledge to the identification and clarification of the interfaces of the Bakerloo Line Extension with its environment.

As well as the gap in comprehension of the interfaces of transport infrastructure and its environment, he also identified that there were seemingly no standardized multi-disciplinary approaches to gathering, validating, and publishing evidence-based data relative to the interfaces. Nor was there sufficient, accessible data that could assist individual professionals within transport organisations and their stakeholders to make effective organisational and urban planning decisions.

Advancing the field

To develop a standardized approach to analysis of railway interfaces, through his experience at TfL (2008-2020) and his PhD research (2014-2019), Darroch developed a Conceptual Framework to represent the interconnected and interdependent complexity of the presence, property, and protection interfaces. This Framework also outlines the considerations required to clarify how, when, where, and why the interfaces occur. Through discussions with interface asset managers from across the world, and with two fellow transport asset management professionals, Darroch went on to develop the Asset Interface Register (AIR) processes.

The AIR processes include standardised approaches for the:

• analysis of the interfaces to determine what, how, where, when, and why they occur;
• gathering of multi-disciplinary evidence-based findings, from that analysis;
• the documentation of those findings within an asset interface register;
• verification (quality control) of the data recorded;
• validation of the findings by asset managers within the transport organisation and its interfacing stakeholders;
• publication and sharing of the AIR data through a web-based GIS interface (here is the proof of concept), to enable visibility across an organisation and with its interfacing stakeholders.

To enable application of the standardised approaches, Darroch developed processes and tools, such as the three levels of analysis:

1. Holistic, the occurrence of the interfaces within their contextual environment;
2. Macro, how the transport infrastructure interfaces with urban infrastructure within its immediate environment; and
3. Micro, detailed analysis of source data to explain how assets forming transport (a tunnel) and urban infrastructure (building foundations) interface:

• levels of comprehension which are required and achieved through each depth of analysis;
• tables of standardised questions for each depth of analysis;
• tables of potential source data archives and required data.

Through the application of these processes, the development of evidence-based multi-disciplinary comprehension and sharing of knowledge will enable:

• implementation of asset data management, BIM, 3D & 4D modelling;
• gathering and sharing of multi-disciplinary evidence-based data relating to what, how, when, where, and why the specific and common interfaces occur;
• development of sustainable transport and urban management policies and planning;
• implementation of more effective infrastructure interface management policies and processes;
• assurance of the safe presence and operation of existing transport infrastructure and its environment;
• creation of, and amendment to, the interfaces between existing and new transport infrastructure and its environment; and
• subsequent organisational and stakeholder cost and time savings, through common accessibility to multi-disciplinary evidence-based data generated through standardised processes, which go some way to meeting the needs and requirements of infrastructure interface managers globally, as demonstrated in the AIR wheel diagram:

Hence the need for the AIR processes and more collaborative approaches to asset interface and asset data management. Especially when different transport infrastructure owners could work together to establish best practices and effect change to current organizational, local, national, and international standards policies and procedures, as all cities share the same problems.

The goal of Dr Darroch’s research, therefore, is to enable the effective sharing of best practices between transport organisations, through benchmarking and continuing discussion of participating professionals in the continuing research. This is expected to improve organisational, urban, and developer standards, policies and procedures for identifying and managing transport infrastructure interfaces with their environment. In other words, save the organisation’s money by proactively identifying existing and future infrastructure conflicts and potentially dangerous, and deadly, infringements, as we saw in the 2013 incident near Old Street Underground, London.