This series has revealed a hitherto unknown complex and often murky relationship between London’s underground railways and its environment. Unsurprisingly in the twenty-first century, with so much of London having been tunneled, excavated, bombed, developed, and redeveloped, much is still unknown of the subterranean environment. Whilst much infrastructure is obvious, there are often foundations, footings, supports, property rights, and other contractual issues that greatly complicate construction, repair, maintenance, and redevelopment.

In this series, we have already looked at the hidden urban interfaces which shape London and the transport asset interface register which keeps track of the complex layers and ownership of public transport infrastructure.

London has long been exploiting its underground. As this cutaway image of King’s Cross St. Pancras Underground station demonstrates, there are many such stations constructed in London that provide interchange between multiple lines, with multiple surface and sub-surface access points. Whilst ostensibly static, changes and improvements are often made, such as the Bank Station Northern line platform widening project, addition of escalators and lifts threading their way through the three dimensional space, and utility cables & conduits. Knowing who owns what, adjacent to what, in the sub-soil is critical to designing, constructing, and maintaining such assets.

King’s Cross St. Pancras Underground station cutaway

Furthermore, there are Roman building remains in the City, plague pits, Bazelgette’s sewers, to buried pneumatic tubes connecting the centre of the Empire, to abandoned stations, tunnels, and even rail lines. As a result London has one of the most crowded and closely packed sub-soil infrastructure environments in the world:

Embankment cross-section shewing utilities (1, 2), & a pneumatic railway tunnel (4) heading under the Thames

In the above image, the Waterloo & Whitehall pneumatic railway tunnel, across the bottom of the frame, was actually started, but it was abandoned due to the 1866 financial crisis. More on this will be expanded upon in a separate article.

The infrastructure context

Henceforth this series has been looking at railway infrastructure from a different perspective – not from the usual civil engineering or operational viewpoints. Instead, we are looking the recently developed field of asset management, which takes into account the aforementioned viewpoints, and adds other multi-disciplinary sectors. Asset management includes the modification for and integration into new urban development, and the addition of new railway infrastructure. Whilst, for instance, the effects of the original Metropolitan line’s construction have been well covered from a civil engineering perspective, what has not is the lasting impact its infrastructure (and that of other lines and railway technologies) have had on urban development.

Interfaces are important, even for abandoned stations

Where station sites have been disposed of, the presence of TfL assets and rights must still be accommodated. Such Brompton Road station on the Piccadilly line, which was closed in 1934, then was sold in the 1940s to the War Department for use as an Air Raid Warning centre. London Underground still owns its passages and part of a former lift shaft, under and within private property, to provide ventilation for the line. The rest of the land and surplus underground infrastructure was sold in 2014 for £53m for private development.

Brompton Road station: platforms are under the road in front. OS 1915

Here is the station and ventilation shaft cross-section looking south-west roughly from the bank location in the above map:

Brompton Road station’s ventilation shaft cross-section looking south-west. Nathan Darroch

Let’s talk about Tube ventilation

The first Tube railways’ lift shafts provided fresh and/or exhaust air ventilation for Tube tunnels, and many of the shafts were retained after the addition of escalator shafts. Most post-1920s tube lines required mid-section shafts due to the longer distances between stations, due to the inadequate ventilation in the original lines. The effects of the piston effect can still be felt at Tottenham Court Road, and the exit from the eastbound Central line platforms. There are more mid-station ventilation shaft examples from this great review of a booklet on inventive vents in London.

The Victoria and Jubilee lines have at least one mid-section ventilation shaft, plus shafts at either end of station tunnels, to reduce the piston affect. New tunnels such as Crossrail have two mid-section shafts for emergency intervention and ventilation, due to the increased distance between stations.

Victoria Line ventilation shaft at Isledon Road, N7. Mike Quinn

Vent shafts were generally built within purpose designed structures, but where necessary they were incorporated within new privately owned buildings. For the Victoria line, most of the standalone shafts (roughly 50 in all) were merely functional concrete blocks up to 50 feet high. An example of the work necessary to identify the location for, design, and construct a ventilation shaft in a long established neighbourhood in Islington is described in this article. Gibson Square is roughly half way between Highbury & Islington and King’s Cross St Pancras stations, so this was one of the few good locations for London Transport to construct a shaft. Here is a shaft that LT constructed about two miles north of Gibson Square:

Obviously, the residents of leafy Gibson Square were not happy with this prospect and campaigned against the unsightly shaft, which they took to London Transport (LT) and the Ministry of Transport. LT agreed to modify the design, and a much smaller shaft was designed to look like a small temple to fit in with the architecture around the park. The pediment above is not actually a roof, but a metal mesh to allow Tube air to escape.

The ventilation shaft at Gibson Square, Islington

Processes of land acquisition in Britain were initially based on canal building principles and early railway methods, then evolved for railway and underground specific characteristics. These affected how stations, tunnels, and vent shafts were designed and constructed.

Land acquisition methods 1845 – 1889

The number of railway construction proposals being received in the early 1840s led to a standardised approach to methods of land acquisition, which was enacted as the Land Clauses Consolidation Act of 1845. Due to the unique nature of the new Underground, land acquisition was authorized by the specific legislation for construction of the Metropolitan Railway in 1853 and 1859.

The sub-surface lines had basic statutory rights and obligations to acquire land by:

right of passage through the subsoil under a road,

compulsorily purchase of the whole or part of land,

requirement to purchase the whole of land and buildings,

an easement to pass under private land and property.

The railway companies constructing the sub-surface underground railways in London argued to be permitted to use the subsoil under public highways, as utilities companies also had a right to the free use of this sub-soil. This has long term effects on the railway environment from both the property ownership, rights and responsibilities, and the engineering perspectives. These perspectives are inseparable from one another.

Between 1863 and 1892, underground railways had to buy all the land required or easements under property:

where they bought land they could retain it, or

sell portions off with protective provisions.

Underground railways legislation provided for the retention of surplus lands for redevelopment or sale. This was contrary to the 1845 Land Clauses Consolidation Act, however, where main line railways were obliged to dispose of surplus lands.

Whence the railway is under a road, it still has presence, property, and protection interfaces, with the road itself, utilities (cables, pipes, sewers) with adjoining property, and physical infrastructure such as foundations and cellars. In addition, more land may have been compulsorily purchased than was evidently necessary, due to clauses within the Land Clauses Consolidation Act 1845.

Land acquisition methods 1890 – present

Whereas the sub-surface railways were required to purchase lands or easements under land, it was more cost effective to take the subsoil under the public highway which was free, wherever possible. This also accommodated existing urban stakeholders’ interest in land. Thus the sub-surface railways run predominantly, but not exclusively, below the public highway.

Construction of tube lines, versus the sub-surface lines, required a change of legislation to account for the different nature of the railways. This was due to the findings of the Report of the Joint Select Committee of the House of Lords and the House of Commons on the Electric & Cable Railways (Metropolis), 1892, which recommended amendments to application of the 1845 Act. So after 1892, land acquisition was possible by:

compulsory purchase of land for station sites,

buying easements under private property, and

right of use of the subsoil under a public highway.

The last two did not confer any property ownership to the railway company, but:

they did grant rights for the railway’s presence, and

they imposed indirect responsibilities on property owners.

For the second point, the property owners’ responsibility was to not adversely affect the safe presence and operation of the railway infrastructure under or adjacent to their property.

Where land was acquired through easement, the railway had no ownership of that subsoil and therefore could not impose protective provisions.

From the 1920s, it became common for extensions to the tube railways to pass under property, through the purchase of easements, enabled through government funding for major projects, through the Trade Facilities Act 1921.

The most recent volume of Survey of London dealing with Oxford Street mentions an interesting legal aspect. Gordon Selfridge, Bourne and Hollingsworth and other major Oxford Street retailers had launched litigation against the Central London Railway (CLR) in the 1920s for nuisance, due to the then locomotive hauled trains causing significant vibration to their properties. The case was decided in favour of the CLR on the grounds that they were a statutory undertaker and could not be pursued for nuisance arising from their authorised operations. In any case, the CLR quickly abandoned loco traction, no doubt because of damage it was doing to their own track, rather than the damage to adjacent buildings.

Furthermore, the foundation depths of buildings built starting in the 1950s were considerably deeper than they had been previously. This increased the relationship between the railway and private property, but not necessarily from an engineering perspective.

Land acquisition methods 1955 – present

For the first new Tube line since the 1906 Piccadilly and Bakerloo railways, the Victoria Line in 1955 was designed to pass for considerable distances cutting under the street pattern. As such, new legislation was passed to facilitate the ability to acquire land by:

compulsorily ‘taking’ the land required on the surface,

compulsorily ‘taking’ the sub-soil required for the tunnels, and

paying compensation for loss of land or sub-soil, where there was an adverse effect on proposed urban development.

Note that the process of ‘taking’ is not purchase:

the sub-soil was considered worthless to the majority of property owners as they had no use for it, and

only those property owners with proposals to use subsoil before a specific date gained compensation.

Notably, this change in land acquisition had little effect on property development at that time, due to the low height and depth of most buildings. The main effect of this new railway was at interchange station locations, where existing stations were increased in size and capacity below ground, as:

this could affect the presence of existing buildings, and

as well as affecting the presence, property, and protection interfaces between the railway and those buildings.

By the 1960s, however, mass redevelopment of areas in London saw taller buildings with deeper foundations. Such designs now posed a potential risk to those tube tunnels constructed under property.

Starting in 1965, London Underground could also ‘take’ additional land or subsoil for the protection of the railway, in the form of an annulus or sleeve of property interest in land or subsoil around the railway. This was hoped to minimise the effect of building and other infrastructure foundations on the tunnels.

Another factor from this period was the introduction of agreed areas of protection, where the London County Council were planning mass redevelopment, and agreement for protective measures on land near or above the railway was made. This protection is also still applicable today.

Many thanks to Dr Nathan Darroch for his insights into the underground world of infrastructure rights. He continues his research in the field.

Header image is of the Camberwell subway vent, looking like a submarine with the tall stack appearing as the sail. Photo by Judy Ovens.

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