The British Way of Building Rapid Transit
By a more than 2-1 vote among my Patreon backers, the third installment in my series about national traditions of building urban rail is the British one, following the American and Soviet ones. While rapid transit in Britain outside London is even smaller than in the US outside New York, the British tradition is influential globally for two reasons: first, Britain invented the railway as well as urban rapid transit, and second, Britain had a vast empire much of which still looks up to it as a cultural and scientific metropole.
Nonetheless, despite the fact that all rapid transit traditions technically descend from London’s, it is worthwhile talking about the British way. What London built inspired and continues to inspire other cities, but many, mainly in the United States, Japan, and Continental Europe, diverged early, forming distinct tradition. As I noted in the post about the Soviet bloc, Moscow was heavily influenced by British engineering, and its own tradition has evolved separately but began as a more orderly way of reproducing the London Underground’s structure in the 1930s.
In taxonomy, this is called a paraphyletic group. Monophyly means a taxon descending from a single ancestor, for example mammals; paraphyly means a taxon descending from a single ancestor excluding certain monophyletic subgroups, for example reptiles, which exclude mammals and birds, both of which descend from the same common ancestor.
The invention of rapid transit
Like most other things Britain became known for, like constitutional government and colonialism, rapid transit evolved gradually in London. Technically, the first railway in London, 1836’s London and Greenwich, meets the definition of urban rapid transit, as trains made some local stops, ran every 20 minutes, and were grade-separated, running on brick arches. However, it is at best an ancestor of what we think of as rapid transit, since it lacked the really frequent stops of the Underground or the New York els.
The first proper rapid transit line in London, the Metropolitan line, opened in 1863. It, too, lacked some features that are standard on nearly all rapid transit systems today: most importantly, it was not self-contained, but rather had some through-service with intercity rail, and was even built dual-gauge to allow through-service with the Great Western Railway, which at the time had broad gauge. Trains ran every 10 minutes, using steam locomotives; to limit the extent of smoke in the tunnels, the line was not fully underground but had a long trench between King’s Cross and Farringdon.
The Met line and the second Underground line, 1868’s District line, were both built cut-and-cover. However, whereas Met line construction went smoothly, the District line had to carve a right-of-way, as the city did not have adequate wide streets for serving the proposed route. The areas served, Kensington and Chelsea, were even then a tony neighborhood with expensive real estate, and the construction costs exploded due to land acquisition. In today’s terms the Met line cost about $32 million per kilometer and the District $90 million, a record that among the historical lines I know of remained unbroken until New York built the Independent Subway System in the 1930s.
The Met and District met to form a circle, and in general, London loved building circular lines. In addition to what would be called the Circle line until a revision last decade, there were two circles farther out, called the Middle Circle and Outer Circle. These were run by mainline railroads; there was still no legal distinction between the two urban railroads and the mainlines, and through-service and even some freight service continued on the Met well into the 20th century, which the company used as an excuse to delay its merger with the other Underground companies.
Even electric rapid transit took time to take shape. After the bad experience with the District line, there was no more cut-and-cover in Central London. The next line to open, 1890’s Northern line, required the invention of deep boring and electric traction; it was not the first rail line to use electricity, but was the first excluding streetcars. However, while the line looked like a normal self-contained rapid transit line, it was pulled by electric locomotives; electric multiple units only came a few years later, starting haphazardly in Liverpool in 1893 (each car required separate controls) and in the more conventional way on the Chicago L in 1897.
Spontaneous order and radial network design
Among the inventions that came out of London was the radial network design. Unlike the physical inventions like underground rail and electric traction, this was not a deliberate choice. It evolved through spontaneous order, owing to the privately-funded nature of British railways. A British railway had to obtain the approval of Parliament to begin construction, which approval would also permit compulsory purchase of land along the way, but funding was entirely private. An early proposal for an underground railway, an 1860s route running what would later become the Charing Cross branch of the Northern line, was approved but could not secure funding and thus was not built.
The upshot is that with private planning, only the strongest lines were built. The strongest travel demand was to the center of London, and thus the lines were all radial, serving either the City of London or the West End. There was no circumferential service. While there were many circles and loops, these were conceived as reverse-branches allowing some railroads to access multiple Central London terminals, or as ways to join two radials like the Met and District without having to go through the difficult process of turning a train underground in a world in which all trains had to be pulled by locomotives.
The same preponderance of radial lines can be seen in other privately-planned contexts. Today, the best-known example is the matatu network of Nairobi. It is informal transit, but has been painstakingly mapped by urbanists, and the network is entirely radial, with all lines serving city center, where the jobs requiring commuting are.
Despite the private planning, London has only a handful of missed connections between lines: it has eight, but only one, between the Met line and the Charing Cross branch of the Northern line, is a true miss between two lines – the other seven are between parallel outer branches or between two lines that intersect a few times in close succession but only have one transfer (namely, the Bakerloo and Met). This is not because private planners build connections spontaneously – Parliament occasionally demanded some minor route changes, including interchange stations at intersections.
The role of regional rail
Like rapid transit, regional rail evolved in London in a haphazard fashion. The London and Greenwich was a mainline railway and the Met line had some mainline through-service, and even the deep-level tube lines are compatible enough with mainline rail that there is some track-sharing, namely between the Bakerloo line and the Watford DC line. The trench between King’s Cross and Farringon was widened to four tracks and turned into a north-south through-route in the 1870s but then abandoned in the 1920s and only reactivated in the 1980s as Thameslink.
The upshot is that London ended with the bones of a regional rail network but no actual service. The ideal was self-contained Underground lines, so even when connections suggested themselves they were not pursued. For example, the original proposal for an underground line between Euston and Charing Cross involved some through-service to the railways at both ends, but when the line was finally built as the Charing Cross branch of the Northern line it was not connected to the mainline and only took over minor branches in suburban North London.
While British planners did eventually plan for through-service – plans for Crossrail date to World War Two or just afterward – by then London was not innovating but rather imitating. By the war, Berlin had already had two S-Bahn through-lines, Munich was planning one, and Tokyo had three. The modern design for Crossrail is best compared with the RER A, in a city London has treated as its primary competitor for a long time now.
Exporting London’s network design
Moscow was heavily influenced by London early on. Later on, Singapore and Hong Kong both drew on British engineering expertise. London’s status as the first city to build rapid transit may have influenced Moscow, but by the 1920s New York had surpassed it in city size as well as urban rail ridership. Moscow’s drawing on London was as I understand it accidental – the chief engineer happened to have London connections – but in Singapore, Hong Kong, Australia, and so on the relationship is colonial, with extensive cultural cringe.
In all of these non-British cities, the British design as exported was cleaner. What I mean is, the systems have a radial structure like London, but the radii are cleaner in that two lines will generally cross just once, especially in Moscow; it’s not like London, where the Central line is always north of the District line, meeting once in a tangent at Bank and Monument, or where the Victoria line and Northern line cross twice.
Another cleaner aspect is the transfer experience. Singapore and Hong Kong both make extensive use of cross-platform transfers between otherwise perpendicular lines; London only does sporadically, on the Victoria line.
A third aspect is uniformly wide interstations. London’s average interstation is about 1.25 km, which is what I think of as the standard because it is very close to the average in Tokyo and Mexico City as well, and at the time I started tracking this statistic in the late 2000s, the Chinese systems were still small. Moscow’s average is 1.7 km, and Singapore’s is similar. Hong Kong is actually divergent there: the MTR mixes core urban lines averaging about the same as in London with the more widely-spaced historically mainline East and West Rail lines and the airport express.
The relative paucity of circumferential rail is hard to judge in the export cases. Moscow came up with the idea for the Circle Line natively; there is an urban legend that it was accidentally invented by Stalin when he left a coffee cup on the map and it stained it in the shape of a circle. Hong Kong doesn’t have much circumferential rail, but its geography is uniquely bad for such service, even more so than New York’s. Singapore does have a Circle Line, but it’s one of the two worst-designed parts of the MRT, with a reverse-branch (the other one is the self-intersecting, connection-missing Downtown Line).
At the same time, it’s worth viewing which aspects British-influenced systems are getting rid of when designing cleaner version of the Underground. The most important is regional rail. Singapore has none: it has a legacy narrow-gauge rail line to Malaysia, but has never made an effort to take control of it and develop it as an urban regional rail line.
Another negative aspect exported by London is the preponderance of deep boring. I made the same complaint when discussing the Soviet bloc: while London is poor in wide arterials that a cut-and-cover subway could go underneath, Moscow is rich in them, and the same is true of Singapore.
Does this work?
London invented rapid transit as we know it, but it did so gradually and with many seams. In some sense, asking if this works is like asking if rapid transit as a technology works, for which the answer is that it is a resounding success. But when it comes to the details, it’s often the case that London has accidental successes as well as accidental mistakes.
In particular, the fact that London almost invented regional rail is a source of endless frustration and extensive retro-crayon. The Met line is almost a 19th-century Crossrail, the Widened Lines are almost a 19th-century Thameslink, and so on. Instead, as time went on the trend has been toward more self-contained lines, which is good for reliability but not when there are self-contained slow tracks of mainlines to hook into, as is planned for Crossrail and as has sporadically been the case for the Watford DC line.
The British focus on radial systems has generally been good. To the extent London has underused metro lines, it’s not because they are poorly-routed as some of the lines in Paris are, but because they serve areas that have many urban rail lines and not a lot of population density; London is not a dense city, going back to the Victorian era, when it standardized on the rowhouse as the respectable urban housing form rather than the mid-rise apartment of Continental Europe or New York.
To the credit of British-influenced planning, Singapore has managed to fit a circumferential line into its system with good connections, just with an awkward reverse-branch. London’s own circumferential transit, that is the Overground, misses a large number of Underground connections due to its separate origin in freight bypasses and mainline rail reverse-branches, where Parliament saw no point in requiring interchange stations the way it did on the Tube. However, the cleaner version seen in Singapore only misses connections involving the Downtown Line, not the Circle Line.
What is perhaps the worst problem with the British style of design is the construction cost. The Northern line was not expensive – in today’s terms it cost around $35 million per km, give or take. However, after WW2 a gap opened between the cost of cut-and-cover and bored metros. The Milan method for cut-and-cover built a subway for around $45 million per km a few years before London bored the Victoria Line for $110 million. Britain exported its more expensive method, which must be treated as one factor behind high construction costs in Singapore, Hong Kong, Australia, and New Zealand; in New Zealand the regional rail tunnel is expensive even as electrifying the system was not.
In the future, cities that wish to build urban rail would be wise to learn from the network design pioneered by London. Urban rail should serve city centers, with transfers – and as in the subsequent refinements of cities that adapted London’s methods to their own needs, there should be some circumferential transit as well. But if mainlines are available, it would be wise to use them and run trains through on the local tracks where available. Moreover, it would be unwise to conduct deep boring under wide streets; elevated or cut-and-cover construction is well-suited for such avenues, causing some street disruption but producing considerable less expensive lines.
Pedestrian Observations 
Nice post. Interesting history!
I don’t totally agree with several of the takes. First, it is probably true that London historically lacked cross-platform transfers, but more recent additions benefit from them, for example, extensive cross-platform transfers between Jubilee Line and DLR. (East London is the most interesting London in 2019…)
Second, I’m not really sure what you mean by “the British focus on radial systems”? I guess historically the system was radial, but the focus in recent decades has not really been on radial stuff, but instead on cross-city stuff and through-running. Overground is a distinctly non-radial system.
I’m not going to start on the construction costs question because it is tired. Nonetheless, I have issues about the concept of what the hell we actually mean by ‘regional rail’? The Metropolitan Line runs to Amersham. The Central Line runs from Ealing to Epping?
Yes, the Overground is definitely circumferential, but fitting it into the network has been a challenge. Unlike Paris, London hasn’t really built greenfield circumferential rail – the Overground and Tramlink are cobbled together from reverse-branches and loops from the 19th and early 20th centuries. So they cross a lot of radials without interchange, and they’re also in a much lower-density area than where T1, T2, T3, and the future M15 run.
Cross-city service is still radial… the Central line has cross-city service in that one train gets you from Ealing to past Stratford, but it’s radial service rather than part of a grid like the systems in Paris, Berlin, Mexico City, and Beijing.
The Met line indeed has regional rail characteristics – the distinction exists, unlike in Tokyo or Seoul, but is still fuzzier than here on the pretend-Continent. This is what I mean by saying the technology evolved haphazardly – evidently the line to Aylesbury became mainline in operations (I don’t think it’s even run by TfL) while still sharing track with Underground trains; and Bakerloo and the DC Watford Line interline for only part of the route for reasons I don’t fully understand.
I suppose the main inherent distinction between “regional rail” and metro is the following:
Metro has relatively close stops to create a continuous corridor that is walkable to the metro line. Regional rail has longer distance between stops (no longer creating a continuous walkable corridor, but rather serving discrete, usually preexisting travel nodes) which allows the line to be longer (in distance) while having a reasonable travel time.
I really should blog about the differences between metro and regional rail.
Yes please!
It’s interesting you characterize British metro planning as “radial” when you also point out the circumferential London lines (Circle line, Middle Circle, Outer Circle), while Glasgow also has a circular line, and Newcastle a near-circular one.
Is Glasgow’s line a proper circumferential? Or is it more like the Circle line or the Yamanote Line, i.e. a bunch of radials that run together in a loop for operational reasons that made sense in the 1880s?
As far as I can tell, it was planned as a circular line from the start.
That said, it is roughly tangent to the city center, so it could be characterized as a radial line where the ends meet.
I don’t really want to disagree with any of this … however, having recently read some of the 19th century history of city transit I have come to question why the 1863 Metropolitan is so automatically crowned the first rapid transit. You yourself give several reasons why it doesn’t really qualify. And the point I made just a few weeks ago on this blog (link and extract below), even if one accepted the premise that this kind of trenched steam-train thingy was genuine rapid transit, then Paris’ Peitite Ceinture beat it by almost a decade (8y):
The PC was (and kind of still is) extensive and links all the mainline rail stations in Paris, including what is today the Musée Orsay, and whose tracks now form part of RER-C. Map:
Also, you say “1890’s Northern line, required the invention of deep boring and electric traction”. Rob Bell said the same thing in his tv series, but it is simply not the case. I presume it is in some book, or Wiki, on the history of London Underground but the first deep-bore tunnel using a TBM rather than just excavation was Marc Brunel’s Thames Tunnel (1825-1843) linking Rotherhithe to Wapping. He invented the Tunnel Shield which is what made it possible to create this first-ever tunnel under a river. It is still used today as part of the London Overground which kind of reinforces the point. In fact I recall Rob Bell did an episode on Brunel’s tunnel in one of his earlier series on Engineering Wonders, so it is mysterious to me why he subsequently ignores it.
Just to be clear, my position in the absence of any new evidence or compelling contrary argument, is that the Northern Line is the world’s first proper rapid-transit. Rob Bell says this in the first ep of his series on the London Underground (even if at other times he talks about the Met line). I believe this is supported by the fact that it continues in operation today pretty much the same as when it was opened whereas those early precursors like the Metropolitan line and Paris’ PC no longer exist in anything like their original form or have been discontinued. They were not the model used by anyone, including both host cities, for a modern metro whereas the Northern Line provided the exact model for all others that followed.
Two points:
1. The Petite Ceinture was indeed another example of proto-rapid transit. However, the London and Greenwich is even older. There really was a gradual development from the London and Greenwich as the first urban rail in the world to the slew of lines straddling 1900 defining rapid transit as we know it: the Chicago L, the Paris Metro, the Central line and rehabbed Northern line, the Berlin U-Bahn, the New York City Subway.
2. The Thames Tunnel was the first application of the tunneling shield, but the technology required extensive development before it was suitable for a railway. I don’t remember where I’ve read it, but my recollection is that the Northern line used something a lot more recognizably similar to a modern TBM, just with more staffing required. I don’t think it was just about the invention of electric traction.
Err, no. The London & Greenwich was just London’s first railway (on viaduct) in 1838 which many places were then building, such as Paris’ first rail line from Gare St Lazare (then Embarcadère des Batignolles) to St Germain-en-Laye opened at the same time, 1837. The next few decades saw an explosion is such lines into major cities around the world. The point about the Metropolitan Line and the PC is that they were intra-city lines specifically to try to cope with the huge load of passengers brought into the city by those railways but dumped at the peripheral mainline stations that were not themselves the final destination. As I said the PC connected all the Paris mainline stations –which was initially (1844) only for freight purposes but soon adapted for passenger services. The St-Lazare to Auteuil PC line was entirely within Paris city limits–inside the Thiers Wall–and in fact this line was circular rather than radial (except for the short section into St Lazare).
Re the Tunnel Shield, yes there were improvements in its design and this certainly improved the logistics and economics of building the Northern as the first deep-bore line, but it was still manual and not mechanised at that point. So yes, I think the electrification of tramways in the late 80s was the crucial thing. It was the same with cut-and-cover metro (NYC, Budapest, Paris etc) which also couldn’t be done with coal-steam traction.
I forgot to add that the below-ground Met Line and PC were the first response to their cities refusing to allow the railways to build viaducts (like the London & Greenwich, and many other railways bringing people into London) in their inner city zones. And that trams were caught up in the same surface congestion as all other street traffic (at that time horse-drawn carriages & trams). But because they needed a lot of open trench this wasn’t a viable solution to most of the city. Electric traction is what made deep-bore and cut-and-cover (without being open) possible.
The London and Greenwich had a bunch of local stops and frequent service all day, though, which Parisian railways before the Petite Ceinture did not have.
Cut-and-cover metro was done with steam traction on the Metropolitan and District lines. The New York Central also ran steam trains in the Park Avenue Tunnel stopping at 86th Street in addition to Grand Central, but not with any frequency, and the holes in Park Avenue for steam venting were unpopular.
Coal smoke venting
Brunels’ shield was not really a TBM. It was the forerunner to the Greathead shield, wherein the face was compartmentalized to allow individual miners to excavate and support the face from within the shield. It was not mechanized in any way, the Whitaker machine that was unearthed during the Channel Tunnel excavation was one of the first TBM’s..
Also you don’t need a TBM to mine through London Clay where most of the Underground has been built. The majority of the older Underground lines were built using hand shields and FL22 pneumatic clay spades with cast iron linings. This is now leading to a problem as the wells that used to supply London with water have been switched off and the groundwater has started to rise again…..leading to leaking linings as the old CI linings did not have gaskets. Historically if you had to mine through anything other than the London Clay, such as the Thanet Sands or Woolwich and Reading beds then you would have used compressed air to support the face. Its only in the recent past that TBM’s have been used as the new lines have had to go deeper to get under the River Thames and pass beneath older infrastructure.
London Clay is one of the best tunneling mediums in the world and that has been a driver for many of the vertical and horizontal alignment chosen, the desire to stay within that material and not get into the perched water tables of the Thanet sands, a lesson Thames Water learned the hard way on the Ring Main project. Unfortunately everyone else wants to be in the same material leading to a very crowded underground. Water tunnels, sewer tunnels, cable tunnels, MOD tunnels, Post Office Railway tunnels and many other such facilities. I work for the company that was founded by the designers of the first Northern Line and we have a 3D map of the London underground. When you look at that its not hard to understand why newer lines end up deeper and deeper to avoid conflicts meaning you get into less favorable ground conditions and hence the need for TBM’s. It should be noted that pre cast concrete segmental linings and the slurry TBM were essentially invented by the British as they looked for ways to build new lines ion these ground conditions.
As for costs, construction costs are what they are around the world and this notion that imported designs lead to high costs is a real fallacy. There are only so many ways you design a tunnel lining to withstand the hydro-static pressure and ground load as well as the design loads imposed on it by the TBM. Having worked around the world designing tunnels under different codes, the end result is pretty much the same, whether it be Danish, Turkish, Hong Kong, Australian or US design codes. It matters not whether you are in a former colony or not. Where this may be applicable is in the fire life safety standards, and rail operational standards. This is where the real costs are as they drive size and other considerations for handling of passengers.
Tunnel Vision, 2019/02/17 – 17:08
Good post.
Though I believe I mentioned a few of your points. I continue to disagree that Brunel’s device wasn’t a TBM. Clearly it was precisely that, and this is why it, and he, are rightly famous. And in the Wiki on TBMs he is the first of three names credited in its invention/evolution. (Also I may have misinterpreted you, but Brunel’s shield had 12 separate compartments for the diggers, surely a key feature?) The fact that today’s TBMs are tubular, highly mechanised and automated and far more powerful and fast etc does not remove the fact they both achieve the same objectives. As the continued use today of the Thames Tunnel for part of London’s rapid transit demonstrates. I believe I also mentioned that the tunnelling of the first deep-bore LU line, which became the Northern Line, was equally not mechanised, but as you say, it did the job. London’s substrata is easy tunneling.
On your last para, yes, engineering and physical things tend to converge because the most efficient, least expensive etc wins at each stage. It’s why most pour scorn on Elon Musk’s proclamations he was going to cut the cost of tunnelling by a factor of ten.
Alon, my (long) post has gone into moderation, probably due to a couple of urls in it.
Tx.
I don’t see anything of yours in moderation or in the recent spam queue (I have 3,000-odd comments in the spamfilter but I searched your name and couldn’t find any). If you mean the comment you just sent in, it got published, maybe you just need to hit refresh?
Yes, it appeared after my second post. Please feel free to delete these superfluous posts.
However, let me also mention that the notification system no longer works for me (hasn’t for a few weeks?). I’ve tried re-inscribing but it just tells me I am already subscribed with this email address …
I don’t know if it is accessible to you but maybe you could take a look and see if it is correctly formatted?
Tx.
Okay, I removed your email from the follower list. Can you resubscribe?
Not entirely sure. I tried and this time it came back with an ambiguous message about being already subscribed to 8 sites and could not subscribe to new ones without deleting old ones (or something like that, I’ve lost the message). So I did. Waiting to see. Nothing so far.
OK, it seems it was my gmail spam filter. About a dozen trapped in there from the date it began. Not sure if I’ve fixed it but in any case apparently not a WordPress issue.
Please delete this thread.
I’m not aware of any cross platform interchange between the Jubilee and the DLR. The exemplar was the Victoria Line where it was a deliberate design feature. Such ambition was dropped from the Jubillee planning in the 1990’s sadly. The tubes most innovative period was probably between the two world wars when there was public works construction and modernisation of existing lines even though they were only 20 years old. This was coupled with a visionary management which combined marketing and operational flair and design to provide the worlds leading integrated urban public transport system. Sadly went to pot post 1945 for various reasons some obvious some not. The great innovation recently has been the massive lift in frequencies in the off peak period which has helped drive huge passenger growth.
I can’t find any examples of needless boring in recent British rapid transit projects:
1. DLR was built using existing rights-of-the-way and nice concrete viaducts. Its extensions to the Bank and Lewisham had to be bored because City and South London do not have any decent roads.
2. JLE had to be bored in South London for the very same reason. It runs at grade in the east though.
3. Overground used existing rights-of-the-way
4. Tyne and Wear Metro mostly utilises existing rights-of-the-way, a tunnel was necessary because central Newcastle lacks wide roads (it does have an urban motorway instead of them). Maybe the Haymarket station was a bit of a mistake (it is bored under a relatively wide street), but there might be obscure reasons to bore them
5. Crossrail has to be bored because of a mess that is central London.
Proposals for improved transit in Bristol are would utilise existing rights-of-way.
It is true that Brits bore a lot, mostly because our cities are old and mostly built before wide roads became a popular idea (do we need a tunnel beneath North Orbital? probably not)
Oh, that’s just about rapid transit, obviously, the London end of the HS1 is completely insane (but I have my doubts if this project was even necessary)
Given the insanity of its genesis I might have once agreed. However, it was necessary and much more than that, despite itself, it represents (or represented pre-Brexit) an uncharacteristic bit of confident long-range planning, even if ten years delayed. Not only in the Stratford station but the St Pancras future hub for UK HSR. The trouble is that the UK has so much trouble keeping its mentality out of the austerity mode, wherein the private sector will perform self-regulated miracles of urban and transit (re)development. The BR privatisation fiasco, the London Underground attempted privatisation and the HS1 PPP utter debacle doesn’t seem to cause any serious rethink on these failed strategies. CrossRail should be wildly successful but one wonders if they will understand its real lesson. The Stratford plan remains quasi-dormant or, like Canary Wharf, muddling along in the absence of any strong government leadership. If the forces of Hard Brexit prevail, then all this investment in public infrastructure will probably be for nothing and the opportunity cost will be felt for decades (more). Some of these loons would flood the Chunnel (even as they use their private jets to access their second and third homes in France or Spain or Tuscany etc; oh and Monaco as the UK’s richest guy and a Hard-Brexiteer relocated there last week).
I’d just like to point out that Singapore technically doesn’t do as much deep boring as the term implies – due to fire codes, the Nicoll Highway incident, and such, the authorities are quite reluctant to embrace the tube-style stations you see in Moscow and the MTR’s Island Line.
Boring is only done for tunnels, stations are always built by cut and cover here. That includes the 43m deep Bencoolen station, resulting in a pit of escalators that would make the Jubilee line’s Westminster station blush. And yes, deep boring may have been able to fix the interchange issue at Rochor…
Also, that narrow gauge line got taken over and they built a park on it – whatever local communities it could have served are largely within reach of the Downtown line.
Interesting article. One point in the debate between cut and cover and bored tunnels is the issue of route alignment. In European cities new underground railways will follow the street alignment. In the 1960s and 1970s many German cities replaced street tramways (often on reserved track) sometimes by tram subway/pre-Metro (coined IIRC in Brussels) but often by direct conversion to U Bahn. In contrast, London has made a virtue out of the necessity of deep boring: its alignments often cut against the grain of the street network. To take a simple example, the Victoria line heads north east from Victoria mainline station via Green Park station to Oxford Circus.This is a very useful route for those arriving in London by mainline rail and wishing to visit the main shopping area but it would have been impossible to achieve such a direct alignment by cut and cover, unless you wanted to propose digging past the front of Buckingham Palace, then through a Royal Park and then digging up some of London’s most expensive real estate including Grosvenor Square, which at the time included the US Embassy.
So deep boring is expensive but it can have advantages in linking origins/destinations by the shortest route, especially for cities with an irregular street layout.