Bangkok keeps building rail lines outward

I rode three new rail transit lines while in Bangkok last month: the extension of the MRT Blue Line west to Lak Song; the MRT Blue Line connection between Tao Poon and Tha Phra; and the BTS Light Green Line extensions to Kheha and Kasetsart University. Except for the relatively short part of the MRT line that extends from Hua Lamphong through Chinatown and Rattanakosin then under the Chao Phraya River, these lines are all elevated, so it’s easy to get at least a rough sense of what the areas they pass through are like.

Rail transit lines and pedestrian facilities in the Bangkok area. “U/C” = under construction. The lines labeled “U/C I” are scheduled to open over roughly the next year. The lines labeled “U/C II” are supposed to open in two or three years. Base GIS data from the Geofabrik versions of OpenStreetMap, modified somewhat.

What struck me most about all three lines was that the territories they traverse have fairly modest densities. The built environment along the lines consists mostly of smallish apartment buildings, row houses, factories, and ground-floor automobile-oriented retail establishments. There are a few taller apartment buildings, but they are in the minority. There are also a couple of shopping malls, but most commerce along the lines is pretty small-scale. There is a huge amount of traffic almost everywhere. Here’s a photo looking west from the Lak Song Station.

Looking west from the Lak Song station on the westernmost station on the MRT Blue Line, Bangkok.

Because the stations themselves tend to be located in pedestrian-unfriendly territory at some distance from the places passengers are actually coming from or going to, the rail lines need some help. There are always taxis, motorcycle taxis, buses, and vans waiting at the stations for passengers.

Looking north from the Kheha station on the BTS Light Green Line. Note the modest height of most buildings and the waiting taxis on the right.

The stations in these modest environments can seem overwhelmingly large-scale.

The Kheha terminus station on the BTS Light Green Line. The station (like most elevated stations in Bangkok) includes an elaborate mezzanine with a few shops.

When you consider that the new lines all use heavy-rail equipment and have frequent service, the routes chosen seemed in some respects a little odd. It wasn’t surprising that, for the several kilometers nearest their terminals, the trains I was in were all rather empty even during rush hour.

Passengers waiting for a signal to enter an MRT Blue Line train at the terminus station, Lak Song.

Of course, rail transit lines are often emptier near their endpoints than in the central city, but Bangkok’s lines—jammed near the new CBD around Siam Square and along Silom and Sukhumvit Roads—are an extreme example of this tendency.

It’s pretty clear that the lines’ apparently odd geography is rooted in the distinctive urban geography of Bangkok. The Bangkok Metropolitan Area is huge. The most recent (2019) edition of Demographia World Urban Areas puts its population at 16,045,000. But Bangkok is not a particularly dense place by Asian standards. Demographia World Urban Areas says that Bangkok covered 3043 square kilometers.¹ That means that it had a population density of 5,300 per square kilometer. In other words, it was a tenth as dense as Hong Kong, a fifth as dense as Singapore, and a third as dense as Jakarta.²

There are any number of reasons for Bangkok’s relatively modest population density. The city, of course, has few topographic or political barriers to expansion. Then there is the fact that most Thais if they can tend to prefer living in single-family houses or row houses, although many end up in smallish apartment buildings. Just as in the United States, only a minority prefer (or can afford) to live in inner-city high-rise apartments.³ Another reason for Bangkok’s diffuseness may be the fact that Bangkok came rather late to rail transit. Much of its growth occurred during a period when the assumption was that most movement would occur by private motor vehicle, and residential and commercial buildings outside the central city (and even informal settlements) tend to include space for parking. Finally, less of the city has been built or planned by the government than is the case with many Asian cities, notably Singapore and Hong Kong. There is only a modest public-housing program, and the government has not been very authoritarian about what should go where. It has also had a pretty laissez-faire attitude toward automobile ownership. Curiously, it has not been very energetic about building roads either, except perhaps freeways, which makes Bangkok’s sprawl an even more difficult problem than it might otherwise have been. There just isn’t enough space on Bangkok’s highways for all the vehicles that Bangkok’s residents own.

One of the consequences of Bangkok’s car-centric development is that not only its housing but also its higher-order commercial and administrative functions are quite spread out. The city doesn’t appear to have a very clearly articulated hierarchy of sub-centers, and its newish central business district, maybe 5 km east of the old center of Rattanokosin on the Chao Phraya River, is also rather diffuse, although perhaps no more so than central business districts in places like Manhattan, London, or Tokyo. As in New York and London, the major CBD functions of high-end retailing, office work, and entertainment are scattered over a dozen or more square kilometers. Its CBD, in other words, is big enough so that movement within it often requires mechanical transport of some sort.

Bangkok’s diffuseness obviously presents a problem if you’re planning a rail system. Rail systems work best when they can focus on important nodes. If nodes are dispersed or not all that important to begin with, rail systems are going to fit the urban landscape awkwardly at best.

Bangkok reluctantly started work on a modern rail transit system only when the problems of its car-centric development became obvious to all. By the 1980s its freeways and—even more—its arterial highways were so overburdened that traffic at certain times of day could hardly move. Furthermore, air pollution levels were absurdly high. The development of urban rail transit seemed the only way out. An additional push in this direction was given by the fact that visitors to the city increasingly found the absence of any serious modern rail system strange.⁴ And what visitors say has increasingly mattered as Bangkok has become an ever more important tourist destination (it’s been claiming in recent years to be the most visited city in the world).

The early years of rail development were not very happy ones (see my earlier post), and the result was a bit haphazard, but, after the two Green Lines opened in 1999 and the Blue Line followed in 2004, Bangkok at least had rail transit stations over much of its new CBD, and even had a rail connection to Suvarnabhumi Airport when the Airport Rail Link opened in 2010, although the absence of fare integration or easy connections among its three separate systems was clearly a barrier to their full use.

In recent years, the government has become a much more important force in planning rail transit. Most of the conversations on the subject of where the lines should go, and most of the documents about this are quite reasonably in Thai only. Unfortunately, I don’t read Thai, but I’ve been able infer the general outlines of these plans from talking with people and reading news stories in the Bangkok Post.

The overriding goal of transit planning in recent years has been to bring rail transit to as much of the city as possible. Because subways are so expensive to build, especially given Bangkok’s high water table, most of the new lines are elevated railways, and the critical thing has thus been finding corridors wide enough to run them along. This alone explains the distinctive patterns of the recently opened extensions of the Light Green and Blue Lines. They were built over fairly straight roads that take them a long way from the central city. This is especially true of southern Light Green Line extension, which runs 23 stops—and 45 minutes—from Siam Square. Its terminus is near the point where unambiguously urban structures peter out.

Additional construction on a very large scale is now under way (see map above). One of its distinctive characteristics is that none of the new lines will serve the central city at all. All the new lines are being built along corridors where construction of elevated rail lines is fairly straightforward. The Light and Dark Red Lines that may open this year run along railroad corridors and will terminate at Bang Sue. An impressive new railroad station is under construction here, several kilometers north of the new CBD, but it’s not a major destination yet. Bang Sue does have connecting Blue Line service. The Dark Red Line passes near the old Don Mueang Airport and is supposed to reach Thammasat University eventually, but it generally traverses a corridor whose most distinctive characteristic may be that massive amounts of stop-and-go traffic run through it. The Orange, Yellow, and Pink Lines on which construction has begun but that probably won’t be functional for two or three (or more) years serve a vast area in eastern and northern Bangkok and also completely miss the central city. They are described as “feeder lines” in some of the official literature.⁵

When these lines are finished, northern and eastern Bangkok will have a thin grid of rail lines, built for the most part over major highways and railroads in territory where traffic is heavy, sidewalks are irregular, and walking is difficult. But, even aside from the pedestrian-unfriendly territory through which these lines are being built, there is the issue that most passengers bound for central-city destinations like Siam Square or Silom Road will have to change trains. Thus, many of the journeys will take quite some time, especially as all of the trains will make stops fairly frequently. (The distance between stations will vary but seems to average something like a kilometer.) Because there will not be any new lines in the CBD, it’s likely that trains on the existing Blue and Green Lines will become even more crowded during the middle parts of their runs than they are now. (There is a possibility of using longer trains on these lines and running some trains over only part of the right-of-way, something already done on the Light Green Line.) An outsider like me, used to rail lines in dense, walkable neighborhoods, can’t help but wonder how many passengers will actually make their way to the stations on these new lines. Let me add, however, that the Airport Rail Link, which runs through similar territory, has had no trouble attracting riders. Its builders thought of it as a line that would mostly serve airport passengers. Plenty of airport passengers do use it, but it turns out that the vast majority of riders are commuters going to and from destinations in eastern Bangkok other than the Airport. Bangkok’s residents are used to difficult commutes.

I’m fascinated by the seriousness with which Bangkok’s planners have moved toward adding rail to a city that until the last couple of decades did not have modern rail lines at all. Due to the absence of such rail lines and a determinedly laissez-faire attitude to development and motor-vehicle ownership, Bangkok (like Jakarta and Manila and many other big cities in middle-income countries) has become a diffuse and sprawling place that rail lines arguably are destined to fit awkwardly. I have no idea whether the result of the new rail construction will be (as some are certainly hoping) to nudge Bangkok in the direction of becoming a denser and less automobile-dependent (and “greener” and less polluted) city. Rising property values along the rail lines and substantial amounts of new construction around the new CBD might suggest that the city is indeed becoming more concentrated, at least to a limited extent, but these changes may be connected with displacement of poor people to the periphery and their replacement by a smaller number of the wealthy. That is, rail construction could (as in some other places) be encouraging sprawl as much as greater concentration. I haven’t seen figures but suspect that much (and maybe most) new construction in Bangkok is far from the CBD and not necessarily anywhere near the new rail lines. I don’t in any case see much sign that an autocentric culture is being tamed in any way.

Most of the conversation on the new rail lines focuses on their theoretical ability to reduce traffic congestion and air pollution. But it’s not lost on anyone who thinks about these things that Bangkok, a hot city much of which is barely above sea level, is one of the places likely to suffer most acutely from climate change. There isn’t much that Thailand can do on its own to stop sea-level rise, but the national government is quite aware that it needs to do something. It’s signed the Paris Agreement, and it’s taken numerous steps to implement it. For example, it’s converted some coal-burning power plants to natural gas. The new rail lines are supposed to be laying the groundwork for a substantial modal shift away from the automobile and hence an additional reduction in greenhouse gas emissions. Only time will tell whether this is a pious hope or a realistic scenario.