Thailand is in the process of expanding and duplicating railway lines across the country. While this is a much-needed improvement to the railway network, the choice of railway gauge will create further problems and cost more in the future.
Thailand’s railways operate on a metre-gauge. There are several gauges used around the world, but most modern railways have settled on using standard-gauge (1,435 mm). This is the gauge used by the Laos-China Railway, and through to China, Central Asia, and Europe.
Like most of Southeast Asia’s railways, Thailand’s railways run a single track, so trains use the same track in both directions Trains have to wait at passing loops to let opposing trains pass. If one train is late, it causes delays throughout the rest of the day.
[Train waiting at passing loop for a train to pass.]
Thailand is now converting these lines to double tracks, so trains can run in both directions without being held up at passing loops. The problem is that there are lines that would have made sense to convert to the standard gauge. Instead, a network is being built that will have mixed gauges.
This problem of a mixed-gauge network was brought up by the president of the Engineering Institute of Thailand in 2015. The recommendation was to stick to a specific width or expect “sky-high costs”.
The State Railways of Thailand (SRT) have been hemorrhaging baht for decades, and in November 2021 it was reported that “its balance sheet shows liabilities of about 160 billion baht, when its actual liability stands at 600 billion baht”. That’s nearly 18 billion USD! The SRT plan to offset this debt by with 600b baht in land projects over 30 years.
Early in 2022, I visited some of the cities where the double-tracking of the metre-gauge is taking place. These cities are also planning for a standard-gauge high-speed railway. After visiting these sites I’m not surprised that the SRT is losing so much money, and what they are doing now is going to make their debt crisis even worse.
The railways of Thailand are divided into regional groups, so this article will break down the problems within each region.
Thailand Railway Map
[Map via aseanrailways.org.]
The current lines referred to in this article are shown on this map.
Northeastern Line: consists of the branches to Nong Khai and Ubon Ratchathani. The absurdity of Thailand’s mixed-gauge mess is best illustrated in the Nong Khai corridor.
[Train to Nong Khai.]
The current Bangkok – Nong Khai line is a single track metre-gauge line with trains using diesel-powered engines. There is also a cross-border shuttle from Nong Khai to Thanaleng in Laos (about 20 km from Vientiane).
[Nong Khai to Thanaleng shuttle train.]
There are two projects that are being built simultaneously in the Bangkok – Nong Khai corridor.
The first project is the double-tracking of the current metre-gauge line.
[Preparing metre-gauge duplication, Bangkok to Nakhon Ratchasima.]
The second project is the high-speed standard-gauge railway that will eventually connect to the Laos-China railway in Vientiane.
This means that Thailand is building two separate railway systems for the same route.
The double-tracking of the metre-gauge railway can be seen in Khon Kaen City. An elevated railway has been built through the city, with an elevated station replacing the old Khon Kaen Station.
[Elevated double-tracked metre-gauge railway and the old single-track metre-gauge railway in Khon Kaen.]
Khon Kaen Station has four platforms, all of which serve metre-gauge lines.
[Metre-gauge line at Khon Kaen Station.]
There is no provision for a standard gauge railway at the new Khon Kaen station, so the tracks will either have to be ripped up or there will be another station for the high-speed railway. Neither of these options is good.
[Khon Kaen Station.]
The high-speed railway will travel at a speed of up to 250 km/h, while the Laos-China Railway is a semi-high-speed railway with a top passenger speed of 160 km/h. It would have made more sense for Thailand to have just built a semi-high-speed railway to the same specifications as the Laos-China Railway and not have proceeded with the duplication of the metre-gauge railway.
What is even more illogical with this dual-gauge corridor is that Thailand will be running freight on the metre-gauge. Freight will then need to be offloaded at a container port to be put onto a standard-gauge railway for its onward journey through Laos to China and beyond.
The Nong Khai corridor is not the only section where the break of gauge at an international border is going to happen. Thailand has now committed to building a new railway line from Ban Phai (on the Nong Khai line) to Mukdahan and Nakhon Phanom. This line has been planned for years as part of the East-West Economic Corridor (EWEC). This line will connect Myanmar to Vietnam by rail, enabling cargo to be shipped inland from either side.
Laos has announced that they will be building their section of the EWEC with a line from Vientiane to Thakhek, and then through Vietnam to the port at Vung Ang (which is majority-owned by Laos). This will be privately built, and the Vietnam section will also be built at the same time.
The Vientiane-Vung Ang Railway will be a continuation of the Laos-China Railway, so it will be a standard-gauge railway. Thakhek in Laos is opposite Nakhon Phanom on the other side of the Mekong River. The Ban Phai to Nakhon Phanom Railway forms half of the Thailand section of the EWEC. It would make sense to build this as a standard-gauge railway, but it is being reported that it will also be metre-gauge. So the vision of a seamless east-west transport corridor across the Greater Mekong Subregion is being hobbled by Thailand’s insistence on sticking to its antiquated metre-gauge system. Once again, an inland port will need to facilitate the offloading of containers between the two systems. The Nakhon Phanom railway is still only at the point of clearing land, so they still have time to change course and build a standard-gauge line.
[Thakhek in Laos, viewed from Nakhon Phanom in Thailand.]
The Northern Line is the line from Bangkok to Chiang Mai. There have been proposals over the years to build a new high-speed railway to Chiang Mai, including a Shinkansen-style railway that was proposed by Japan. So far though, the Chiang Mai high-speed railway remains just a proposal.
[Chiang Mai Station.]
There is also a new line that will be built to Chiang Rai, which would branch from the Chiang Mai line at Den Chai. The Chiang Rai line will be a metre-gauge line like the current system. If the Chiang Mai line is ever upgraded in the future to a high-speed standard-gauge railway, then this line becomes incompatible.
The Eastern Line is a hot mess of bad planning whose fortunes are tied to the further bad planning of Bangkok’s urban rail transit system (I will get to that point in the Greater Bangkok section).
The Eastern Line goes from Bangkok to Chachoengsao, then to Chonburi Province on the Eastern Gulf Coast and Aranyaprathet on the border with Cambodia.
The Chonburi branch has a limited passenger service from Bangkok to Ban Phlu Ta Luang via Pattaya. The line extends to Map Ta Phut (home to the largest port in Thailand) for freight services.
[The slow train from Hua Lamphong to Ban Phlu Ta Luang.]
The Ban Phlu Ta Luang service will be replaced by the 3-Airport Rail Link, which will connect Don Muang and Suvarnabhumi Airport to U-Tapao Airport in Rayong (also referred to as Pattaya Airport). This rail link will recycle the current Airport Rail Link from Phaya Thai in Bangkok to Suvarnabhumi Airport. The Airport Rail Link opened in 2010, and it is the only standard-gauge railway in Thailand (not counting urban transit lines in Bangkok). From Suvarnabhumi, the line will be extended to U-Tapao Airport.
The 3-Airport Rail Link will be a standard gauge railway with train speeds of up to 250 km/h. There is also talk of extending this line to Rayong City and Trat (both of which have no railway).
Meanwhile, the current single track that serves Ban Phlu Ta Luang and Map Ta Phut has been double-tracked. This is an important corridor for freight being shipped from the port of Map Ta Phut to Laos via the Northeastern Line.
[Double-tracking of Ban Phlu Ta Luang line.]
Map Ta Phut is effectively a shipping port for Southern China, but with freight being sent to the Laos border on a metre-gauge railway, containers need to be switched to a standard-gauge freight train.
So the Eastern section is also building out a two-gauge system, and neither is the best system for their intended purposes.
For the high-speed line to U-Tapao, does this really need to be a high-speed railway? The current Airport Rail Link is a 160 km/h service (a semi-high-speed railway) and that would have been sufficient for the Pattaya and U-Tapao extension. And of all the places in Thailand that should get a high-speed railway, I would not have put Rayong and Trat on that list (sorry, Rayong and Trat). A semi-fast train on a standard gauge would have sufficed.
For the double-tracking of the metre-gauge railway to Map Ta Phut, it would have been more logical to build a double-tracked standard-gauge railway here, which could then join a double-tracked standard gauge railway in the Northeast, which (most crucially) could be connected to the Laos-China standard-gauge railway.
This could have been done with minimal disruption to the current metre-gauge, and they could still use the metre-gauge until the rolling stock has been completely transitioned to a standard-gauge line.
The Southern Line constitutes lines south and west of Bangkok. The line from Nakhon Pathom to Chumphon is being duplicated, and the second phase will extend further south from Chumphon to Surat Thani-Hat Yai-Songkhla.
Once again this metre-gauge double-tracking project is going ahead without any consideration for future lines.
There have been reasonably serious proposals over the years to build a high-speed railway from Bangkok to Hua Hin. This project was cancelled but has been revived again with a new feasibility study underway.
There have also been passing mentions of a Bangkok to Kuala Lumpur high-speed railway, which would be a continuation of the Bangkok – Hua Hin line further south. Going back even further, a Bangkok to Kuala Lumpur HSR would make up what was the vision of the Singapore-Kunming Rail Link (SKRL).
Progress of the double-track program on the Southern Line can be seen in Hua Hin. A new station is being built in Hua Hin with an elevated track through the city centre (like in Khon Kaen).
[New Hua Hin Station next to the old single-track metre-gauge railway.]
While an elevated railway through the city is a good thing, this is the same problem that is happening in the Northeast. If Thailand decides to build a high-speed railway to the south, where will they put it?
[Single-track metre-gauge railway and the elevated double-track metre-gauge railway in Hua Hin.]
As you can see here in Hua Hin, the new double-track metre-gauge railway is being built alongside the old single-track metre-gauge line. If they do go ahead and built a high-speed railway they will need to build a new elevated track. They could have built this new double-tracked line as a standard-gauge semi-high-speed railway, while still having use of the old metre-gauge railway while transitioning to the standard-gauge railway.
Greater Bangkok: Commuter Railways (Red Lines) And SRT Lines
In Thailand, all railways lead to Bangkok. It is the main hub of Thailand, and Bang Sue Grand Station was built with the vision of being the grand hub of mainland Southeast Asia railways.
[Bang Sue Grand Station.]
Given that an enormous amount of money was spent to build Bang Sue, a better plan should have been made to untangle the railways in and around Bangkok.
[Tracks for metre-gauge and standard-gauge lines at Bang Sue Grand Station.]
The mixed-gauge mess continues with the Bangkok commuter railway project collectively known as the SRT Red Lines. The two new lines (SRT Light Red Line and SRT Dark Red Line) are metre-gauge electric railways.
[Platforms for SRT Red Lines at Bang Sue Grand Station.]
Most of the red lines follow the path of established SRT long-distance lines, and they will eventually replace these lines.
[SRT Red Lines as of 2022.]
The Light Red Line will be extended south from Bang Sue Station, and then east to Phaya Thai and Hua Mak. This line will follow the same route as the current SRT Eastern Line, underneath the current elevated Airport Rail Link.
[Airport Rail Link and SRT Eastern Line at Phaya Thai.]
The Airport Rail Link will eventually become the 3-Airport Rail Link. Instead of building two separate lines on the one route (Light Red Line and 3-Airport Rail Link), this should have been consolidated into one line.
[Airport Rail Link Route (The Light Red Line will also run from Phaya Thai to Hua Mak).]
You can see the problem that the SRT has made for itself when looking west from Phaya Thai BTS Station. The current Airport Rail Link ends here, and there is a bit of line that sticks out in preparation for a future extension. Underneath that is the current SRT Eastern Line which will be replaced by the Light Red Line extension. In the future, there will be an elevated railway for the standard-gauge HSR line from Phaya Thai to Bang Sue, and an elevated railway for the metre-gauge Light Red Line/SRT East, also from Phaya Thai to Bang Sue. No wonder the SRT is 600 billion baht in the hole when decisions like this have been made.
[SRT Eastern Line at Phaya Thai.]
In the future, there will be a high-speed line to U-Tapao on this elevated section (with a possible extension to Tayong and Trat), while the Eastern Line and Light Red Line will be on a meter gauge underneath.
Makkasan Station is another place to see the lack of foresight in consolidating the commuter and long-distance railways in Bangkok. Makkasan was built as the central Bangkok terminal for the Airport Rail Link, though it is now considered a white elephant (I will have another article dedicated to Makkasan).
Makkasan has four platforms that were designed to serve express and stopping-all-station trains to Suvarnabhumi. Underneath the station is the single track of the Eastern Line (the line that goes to Chonburi and the Cambodia border). The double-track Light Red Line will be built along here.
[Makkasan Station and the SRT Eastern Line.]
The commuter line should have been built as a standard-gauge line, with the goal of converting the Eastern Line to standard gauge as well. Then all of the lines could have used the same elevated railway that was built for the airport link.
[Hua Mak SRT Station, with the Hua Mak Airport Rail Link in the distance.]
The SRT Dark Red Line will also be problematic. The Dark Red Line currently runs from Bang Sue to Rangsit, and it will be extended further north to Thammasat University. That will be about halfway to Ayutthaya, which will be served by both the metre-gauge line and the future high-speed railway to Laos. A future high-speed line to Chiang Mai would also be on this route. The Dark Red Line should have been a standard-gauge line, and it could have been consolidated into the network that will serve Bangkok to the Northeast.
The Dark Red Line will be extended south in the future, though this is the most problematic corridor to untangle. The line will be extended south from Bang Sue to Hua Lamphong, replacing the tracks of the current line.
[Line from Bang Sue to Hua Hamphong.]
From Hua Lamphong it is proposed to be extended to Maha Chai, replacing the Wongwian Yai-Maha Chai line. A further proposal extends the line on the path of the Maeklong Railway (famous for the train that goes through a market).
Maeklong is close enough to the Southern Line for it to have been considered a future shortcut from Bangkok to the south, saving about 43 kilometres from the current route.
[Greater Bangkok rail map.]
This is a metre-gauge line though, so such a shortcut would not work for a proposed southern high-speed railway (a line that would want a shortcut).
What Thailand should have done, and what can still be done
Thailand has now embarked on a path of running a railway network with two gauges, committing itself to the expense that goes with it. In 2017, the Office of Transport and Traffic Policy and Planning (OTP) unveiled a 20-year master rail plan for rail development:
“The plan covers double-track rail development, stretching 2,777km; metre-gauge rail routes with a total distance of 2,352 km; standard-gauge rail routes for high-speed trains, stretching 2,457km; the establishment of container yards; and the use of electric trains for rail transport.”
It’s worth noting that the Laos-China Railway officially began construction in December 2016, so Thailand knew that this was going to be a standard-gauge semi-high-speed railway. At that point, Thailand could have just committed to building the same system. Instead, they went ahead with the double-tracking of the metre-gauge and the standard-gauge high-speed railway.
The Laos-China Railway was completed in December 2021, and Thailand was still mired in issues with the construction of the high-speed train that will connect to it. In fact, in the time that China built that railway, Thailand had still not even come to a decision on the railway bridge across the Mekong River. The government was looking for funding for a feasibility and design study on the railway bridge…in 2022.
The SKRL has been a plan for decades, and China committed to the project in 2007. There surely must have been a consensus between the nations of the Kunming-Singapore Railway (China, Laos, Thailand, Malaysia, and Singapore) to build a united line of the same specifications, and then each country would work towards that goal. China has gone ahead and built the China and Laos section on a standard gauge with a semi high-speed railway (160 km/h for passenger trains). A standard-gauge semi-high-speed train would have also been a good option for Thailand. It is cheaper to build than a full high-speed railway, and they could have done this instead of committing to the metre-gauge duplication project.
The double-tracking of the metre-gauge system is so far advanced now that it is too late to consolidate the network to a single gauge. The only change that could feasibly be made now is to reconsider building the Ban Phai-Nakhon Phanom and Chiang Rai lines on a standard gauge before work begins.