Bangkok Mass Transit System

Year:1999 - ongoing


Cost:£2.8bn (Blue Line)

Country: Thailand

What did this project achieve?

Increasing public transport options for 8 million people in the Thai capital

Bangkok suffers from transport challenges like many big cities, especially in Asia. Until 1999, the Thai city’s commuters had just two public transport options. There were boat services, which still run on the Chao Phraya River and on two canals, and buses.

The buses replaced electric trams that were in operation from 1894 to 1968.

However, by the end of the 1980s, it was becoming clear that this transport infrastructure wasn't enough for a growing city of more than 8 million people. To help solve this problem, the Thai government’s Ministry of Transport set up the Mass Rapid Transport Authority (MRTA) in 1992.

The first of the Mass Rapid Transport (MRT) lines, the Blue Line, was opened in July 2004. Also known as the Chaloem Ratchamonkhon Line, it runs for 21km across 19 stations, from Tao Poon Station to Hua Lamphong, where it connects to the central railway station.

The second line, MRT Purple Line, which is known officially as the Chalong Ratchadham Line, opened in August 2016. It runs for 23km across 16 stations, between Tao Poon and Khlong Bang Phai.

They both serve more than 410,000 passengers each day.

A privately financed and operated elevated railway, BTS Skytrain, opened in 1999 and by 2018 was a 55km elevated metro that runs across 25 stations.

Difference the project has made

Thousands of people now have an efficient way of travelling around Bangkok.

Congestion on the roads was reduced, which also led to an improvement in air quality.

How the work was done

Building the first MRT lines was not an easy task. Bangkok is built on water-logged soil, which made constructing massive, deep underground structures a challenge. The 1997 economic crisis also caused delays.

The city is also prone to flooding. This is why all of the metro station entrances are raised about one metre above ground level and have built-in floodgates. The stations are 18m below ground level.

The MRTA is building four more lines – Orange, Pink, Yellow and Brown – in 2018, as well as several extensions.

The new lines are expected to open in 2019 and 2020, and the Purple Line is also due to be extended to the south in 2023.

It plans to extend the Blue Line with two routes that will cross the Chao Phraya River.

One of the biggest civil engineering challenges will be tunnelling under the river, after which the line will come to the surface and split. One section will go along a viaduct further to the west and the other will head north.


If you take Jakarta, that is probably where Bangkok was 20 years ago. Countries like Indonesia look toward Thailand as to where they aspire to go – not Singapore or Hong Kong, which are too developed.

A British engineer, consultant on the metro

Nikkei Asian Review, 22 November 2017

Fascinating facts

People are not allowed to take certain items onto the metro, with the list ranging from items such as flammable goods to the more unexpected balloons and durians. Durians are known for being one of the smelliest tropical fruits in the world.

The BTS Skytrain was opened on 5 December 1999 by Princess Maha Chakri Sirindhorn, second daughter of King Bhumibol Adulyadej.

The MRT metro was opened on 3 July 2004 by King Bhumibol and Queen Sirikit.


People who made it happen

  • Client: Mass Rapid Transit Authority of Thailand (MRTA)
  • Consultant engineers: AECOM, Arup

More about this project

Explore more civil engineering projects

I want to become a civil engineer.

See how your studies lead to a civil engineering career

The job you end up with in civil engineering is likely to link back to what you studied at school, college or university. Here you can see your options at any age.

At school

Up to 16 years

School / college

16-19 years

College / university

18 years +

Change career

Any age