Based on positive feedback from Patreon backers, I am expanding my post about the American way of building rapid transit into a series covering various national traditions. The Soviet bloc’s tradition is the most globally widespread, as Soviet advisors trained engineers in the USSR’s entire sphere of influence, ranging from just east of the Iron Curtain to North Korea. It is especially fascinating as it evolved independently of Western and Japanese metro-building traditions, from its origins in Moscow in the 1930s.

Like the American tradition, the Soviet tradition has aspects that are worth emulating and ones that are not. But it’s useful to understand where the design aspects come from. It’s especially interesting as Moscow has influences from London, so comparing where the Russians did better and where they did worse is a good case study of adapting a foreign idea to a different national context. Similarly, China imported Russian ideas of how to build metro networks while making considerable adaptations of its own, and I hope to cover China more fully in a future post, discussing there too how the tradition changed in the transmission.

Technical characteristics

The Soviet way is characterized by four major features:

Wide station spacing: the average interstations on the systems in question are all long. Moscow’s is 1.7 km, and for the most part cities in the former USSR with metros have similar interstations; in this table, length is in the row labeled 1 and number of stations in the row labeled 3. This is also true of the metro systems in China and North Korea, but in the Eastern European satellite states it’s less true, with Prague and the newer lines in Budapest averaging not much more than 1 km between stations.

Very little branching: Soviet lines do not branch, with a small handful of exceptions. Moscow’s only branching line, Line 4, is unique in multiple ways, as it was redesigned with American influence after Nikita Khrushchev’s visit to the United States. Eastern European satellite state metros do not branch, either, in contrast with contemporary postwar Western European networks like those of Stockholm and Milan. China has more branching, albeit less than Western and Japanese systems of comparable scope.

Radial network design: what I call the Soviet triangle, while not really a Soviet invention (it has antecedents in Boston and London), became a rigid system of network design in the communist bloc. Subway lines all run as rough diameters through the disk of the built-up area, and meet in the center in a triangle rather than in a three-way intersection in order to spread the load. Moscow adds a single circular line to the mix for circumferential travel, subsequently refined by a second and soon a third ring. Here, China diverges significantly, in that Beijing has grid elements like parallel lines.

Deep boring: Soviet and Soviet-influenced metro networks run deep underground. Traditionally, there was limited above-ground construction, for reasons of civil defense; in Moscow, only Line 4 is shallow, again due to American influence.

London’s long shadow

The decision to deep-bore the Moscow Metro was undertaken in the 1920s and 30s, long before the Cold War and the militarization of Soviet society. It even predates the turn to autarky under Stalin; as Branko Milanovic notes, the USSR spent most of the 1920s trying to obtain foreign loans to rebuild after the Revolution, and only when foreign capital was not forthcoming did it turn to autarky. The NKVD arrested the British advisors, conducted show trials, and deported them for espionage in 1933; the basic technical characteristics were already set then.

In London, the reason for deep boring is that the city has one street wide and straight enough for a cut-and-cover subway, Euston Road hosting the Metropolitan line. In Moscow, such streets are abundant. British planners were exporting both the idea of constructing wide throughfares based on modernist planning principles and that of deep-boring metro lines, an invention based on the context of a city that lacks such throughfares.

The network design bears similarity to what London would have liked to be. London is not as cleanly radial as Moscow, but it clearly tries to be radial, unlike New York or Paris. In general, it’s best to think of the early Moscow Metro as like early-20th century London Underground lines but cleaner – stations spaced farther apart, more regular radial structure, none of the little quirks that London’s had to build around like the Piccadilly line’s since-closed Aldwych branch.

Transit and socialism

The Soviet method of building metros may have originated in British planning, but its implementation throughout the 20th century was under socialist states, in which there was extensive central planning of the entire economy. Decisions regarding who got to live in the cities, where factories were to be sited, what goods were to be produced, and which sectors each city would specialize in were undertaken by the state.

There are several consequences of this political situation. First, by definition all urban development was social housing and all of it was TOD. Housing projects were placed regularly in ever-expanding rings around city center, where all the jobs were. There was no redevelopment, and thus density actually increased going out, while industrial jobs stayed within central cities even though in the capitalist bloc they suburbanized early, as factories are land-intensive.

Of note, some of this central planning also existed under social democracy: Sweden built the Million Program housing in Stockholm County on top of metro stations, creating a structure of density enabling high transit ridership.

But a second aspect is unique to proper communism: there were virtually no cars. Socialist central planning prioritized capital goods over consumer goods, and the dearth of the latter was well-known in the Cold War. At the same time, modernist city planning built very large roads. With no cars to induce people to fight for livable streets nor anything like the Western and Japanese New Left, urban design remained what today we can recognize as extremely car-oriented, before there were any cars. Major Eastern European cities are thus strongly bifurcated, between ones where a centrally planned metro has ensured very high per capita ridership, like Prague, Budapest, and Moscow (and also Bratislava, with trams), and ones where as soon as communism fell and people could buy cars the tramway network’s ridership cratered, like Tallinn, Riga, and I believe Vilnius.

The third and last aspect is that with extensive central planning, the seams that are visible in cities with a history of competition between different transit operators are generally absent. The incompatible gauges of Tokyo and the missed connections of New York (mostly built by the public-sector IND in competition with the private-sector IRT and BMT) do not exist in Moscow; Moscow does have missed connections between metro lines, but not many, and those are an awkward legacy of long interstations.

Of note, the autocratic aspects of socialism do not come into play in Soviet metro design. One would think that the Stalinist state would be able to engage in projects that in democracies are often unpopular due to NIMBYism, such as cut-and-cover subways, but the USSR did not pursue them. China does build elevated metro lines outside city centers, but evidently its plans to extend the Shanghai Maglev Train ran into local NIMBYism. People complained that the separation between the tracks and adjacent buildings was much less than in the German Transrapid standards; the Chinese state’s credibility on environmental matters is so low that people also trafficked in specious concerns about radiation poisoning.

The role of regional rail

The European socialist states all inherited the infrastructure of middle-income countries with extensive proto-industry – in particular, mainline rail. Russia had even completed the Trans-Siberian Railway before WW1. The bigger cities inherited large legacy commuter rail networks, where they operate commuter EMUs.

But while there are many regional trains in the European part of the former Soviet bloc, they are not S-Bahns. There was and still is no through-service, or frequent off-peak service. Connections between the metro and mainline rail were weak: only in 2016 did Moscow start using a circular legacy railway as its second urban rail ring.

The situation is changing, and just as Moscow inaugurated the Central Circle, so is it planning to begin through-service on radial commuter rail, called the Moscow Central Diameters. However, this is early 21st century planning, based on Western European rapid transit traditions.

Does this work?

In the larger cities, the answer is unambiguously yes: they have high transit ridership even when the population is wealthy enough to afford cars. The smaller cities are more auto-oriented, but that’s hardly the fault of Soviet metro planning when these cities don’t have metro networks to begin with; the fault there concerns urban planning more than anything.

Three aspects of Soviet metro planning deserve especial positive mention. The clean radial structure best approximates how single-core cities work, and Moscow and the cities it inspired deserve credit for not wasting money on low-ridership tangential lines, unlike Mexico City or (at smaller scale) Paris. It’s not too surprising that the Soviet triangle in particular exists outside the Soviet bloc, if not as regularly as in Eastern Europe.

The second positive aspect is the use of headway management in Moscow. With no branching and high frequency, Moscow Metro lines do not need to run on a timetable. Instead, they run on pure headway management: clocks at every station count the time elapsed since the last train arrived, and drivers speed up or slow down depending on what these clocks show relative to the scheduled headway between trains. At the peak, some lines run 39 trains per hour, the highest frequency I am aware of on lines that are not driverless (driverless metro technology is capable of 48 trains per hour, at least in theory, and runs 42 in practice on M14 in Paris).

The third and last is the importance of central planning. All public transportation in a metro region should be planned by a single organ, which should also interface with housing planners to ensure there is ample TOD. If anything, one of the bigger failures of Soviet metro planning is that it did not take this concept all the way, neither integrating metros with regional rail nor building a finger plan.

In contrast with these three positive aspects, station design is lacking. As frequent commenter and Patreon supporter Alexander Rapp noted in comments, there are some cross-platform transfers in Moscow; however, the initial three lines do not have such transfers, and instead the transfers became congested early, creating the impetus for the Circle Line. The deep-bored stations are expensive: Line 4 was built cut-and-cover to save money, not out of some cultural cringe toward New York, and today Russia is looking at cut-and-cover stations as a way to reduce construction costs.

Moreover, the wide interstations are too clean. The Underground has long interstations outside Central London and short ones within Central London, facilitating interchanges; while London has eight missed connections, these result from seams on lines running alongside each other or on branches, and only one pair of trunks has no transfer at all, the Metropolitan line and the Charing Cross half of the Northern line. In contrast, the relentlessly long interstations in Moscow lead to more misses.

I did a complex Patreon poll about series to write about. In the poll about options for transit network design the winning entry was difficult urban geography, covered here and here; the runner-up was cross-platform transfers.

Subway users have usually had the experience of connecting at a central station so labyrinthine they either were lost or had to walk long distances just to get to their onward train. Parisians know to avoid Chatelet and New Yorkers know to avoid Times Square. It’s not just an issue for big cities: every metro system I remember using with more than one line has such stations, such as T-Centralen in Stockholm, Waterfront in Vancouver, and Dhoby Ghaut in Singapore. To prevent such connections from deterring passengers, some cities have invested in cross-platform interchanges, which permit people to transfer with so little hassle that in some ridership models, such as New York’s, they are treated as zero-penalty, or equivalent to not having to transfer at all.

Unfortunately, improving the transfer experience is never as easy as decreeing that all interchanges be cross-platform. While these connections are always better for passengers than the alternative, they are not always feasible, and even when feasible, they are sometimes too expensive.

Cross-platform transfer to wherest?

Consider the following two-line subway interchange:

A cross-platform transfer involves constructing the station in the center so that the north-south and east-west lines have platforms stacked one on top of the other, with each east-west track facing a north-south track at the same platform. The problem: do eastbound trains pair up with northbound ones and westbound trains with southbound ones, or the other way around?

In some cases, there is an easy answer. If two rail lines heading in the same general direction happen to cross, then this provides a natural pairing. For example, the Atlantic Branch and Main Line of the LIRR meet at Jamaica Station, where the cross-platform transfer pairs westbound with westbound trains and eastbound with eastbound trains. In Vienna, this situation occurs where U4 and U6 intersect: there is a clear inbound direction on both lines and a clear outbound lines, so inbound pairs with inbound and outbound with outbound.

However, in most cases, the transfer is within city center, and there is no obvious pairing. In that case, there are two options.

Near-cross platform transfer

Some transfers are nearly cross-platform. That is to say, they have trains on two levels, with easy vertical circulation letting people connect between all four directions. In Berlin, there is such a transfer at Mehringdamm between U6 and U7 – and in the evening, when trains come every 10 minutes, they are scheduled to offer a four-way timed interchange, waiting for connecting passengers even across a level change.

Multi-station transfer complex

Singapore, Stockholm, and Hong Kong all offer cross-platform transfers in multiple directions by interweaving two lines for two or three consecutive stations. The three-station variant is as in the following diagram:

At the two outer transfer stations, the cross-platform connections are wrong-way relative to the shared trunk corridor: eastbound pairs with northbound, westbound pairs with southbound. At the middle station, connections are right-way: eastbound pairs with southbound, westbound pairs with northbound.

Of note, the shared trunk has four tracks and no track sharing between the two different subways. I’ve proposed this for the North-South Rail Link. The reason three stations are needed for this and not two is that with only two stations, passengers would have to backtrack in one pairing. Nonetheless, backtracking is common: Stockholm has three stations for the transfer between the Green and Red Lines but only the northern one is set up for wrong-way transfers, so passengers connecting wrong-way in the south have to backtrack, and Singapore has two stations between the East-West and North-South Lines, since one of the pairings, west-to-south, is uncommon as the North-South Line extends just one station south of the transfer.

Why are they not more widespread?

The inconvenience of Parisian transfers is a general fact, and not just at Chatelet. Two lines that meet usually meet at right angles, and the platforms form a right angle rather than a plus sign, so passengers have to be at one end of the train to have easy access to the connecting platforms. The reason for this is that Paris built the Metro cut-and-cover, and there was no space to reorient lines to have cross-platform transfers.

In contrast, both Stockholm and Singapore had more flexibility to work with. Singapore deep-bored the MRT for reasons of civil defense, contributing to its recent high construction costs; the tradeoff is that deep boring does permit more flexibility underneath narrow streets, which all streets are compared with the footprint of a cross-platform interchange. Stockholm used a mixture of construction methods, but the four-track trunk carrying the Green and Red Lines is above-ground in the Old City but was built with a sunk caisson at T-Centralen.

In London, similarly, there are cross-platform transfers, involving the Victoria line. It was built in the 1960s around older infrastructure, but at a few spots in Central London, the tubes were built close enough to old lines to permit cross-platform interchange in one direction (northbound-to-northbound, southbound-to-southbound). In contrast, the surface network, constrained by land availability, does not feature easy interchanges.

While deep boring makes cross-platform transfers easier, either can exist without the other. If I understand this correctly, U6 was built cut-and-cover. There were even weaves on the IND in New York, but they were expensive. Moreover, when two lines are built under a wide street with two branching streets, rather than on something like a grid (or even Paris’s street network, which is gridded at key places like where M4 runs under Sevastopol), cut-and-cover construction can produce a cross-platform transfer. Conversely, such transfers do not exist in all-bored Moscow and are rare in London.

The importance of planning coordination

Ultimately, cross-platform transfers boil down to coordinated planning. Some cities can’t build them even with coordination – Paris is a good example – but absent coordination, they will not appear no matter how good the geography is. Stockholm, Berlin, Vienna, Singapore, and Hong Kong are all examples of centrally planned metro networks, without the haphazard additions of New York (which was centrally planned on three separate occasions) or London (where the early lines were built privately).

Even with coordination, it is not guaranteed cross-platform transfers will appear, as in Moscow. Planners must know in advance which lines they will build, but they must also care enough about providing a convenient transfer experience. This was not obvious when Moscow began building its metro, and regrettably is still not obvious today, even though the benefits are considerable. But planners should have the foresight to design these transfers when possible in order to reduce passenger trip times; ultimately it is unlikely to cost more than providing the same improvements in trip times through faster trains.