The reason why Changi Airport EWL branch is to be converted to the Thomson East Coast Line extension

 Why is a conversion needed?

LTA needs to convert the Changi Airport Branch Line (CGL) to become a part of the Thomson East Coast Line (TEL) because there are many problems.

1. Cost of operation in relation to demand

Changi Airport Branch Line is currently part of the East West Line (EWL) since 2001. There are only three stations on the branch, namely Tanah Merah, Expo and Changi Airport. Two trains currently ply the line and the only people who sit the airport line are people going to Changi Airport to take flights. It is a branch line not as conducive as the Circle Line Extension, which also has three stations  - Marina Bay, Bayfront and Promenade, which serve the shopping areas of Marina Bay Sands.

While the Circle Line branch - either to Dhoby Ghaut or Marina Bay, are busy, LTA knows that a branch line is costly to operate because it has side service as opposed to the main line. As for the Changi Airport branch, the other station being served is the Singapore Expo at Expo station, which receives no one unless there is a convention or exhibition happening there. Due to low demand, the cost to operate CGL is subsituted by revenue from existing SMRT rail lines such as Circle Line and Thomson East Coast Line. It will certainly cost an arm and a leg to operate it if demand is at such rate. 

2. Inconvenience of accessing Changi Airport

Changi Airport was connected to the MRT network in 2002 (Expo station opened in 2001). Prior to this, the only way to reach the airport are by taxis or buses. 

When the MRT to Changi Airport opened, there was through service to the airport from the original terminus of Boon Lay. However, due to impractical demand, it was reduced to a branch line operated out of Tanah Merah. This consequently caused people to wait for at least 15 minutes for a train at Tanah Merah station to Changi Airport.

Since 2016, the Land Transport Authority (LTA) has had the desire of increasing the connectivity of Changi Airport. Currently, the government is building a new terminal (Terminal 5) on the east apron of Changi Airport, which will be larger than the existing terminal development and hence will require a new MRT station to be built (Changi Airport Terminal 5). Therefore, the simple solution would be to extend either the CGL or TEL both to serve Terminal 5. However, due to numerous public grievances, LTA had been studying the possibility of seamless terminal-to-terminal accessibility by a single train line. In other words, passengers from either Tanah Merah or Sungei Bedok MRT station can access the airport using the same train and MRT line. If the TEL were to stop at Changi Airport and thus make the airport an interchange station, people will need to change trains and more people will prefer to take the TEL than the EWL CGL to the airport, since the CGL and EWL will be having perfect competition to cater for passengers, and that TEL will have direct MRT connection from the city to the airport without needing a transfer. It would be a shame if the World's Best Airport for almost 15 consecutive years have no direct access from the city to the airport. The other option of reaching the airport by MRT is via the Downtown Line, but it still necessitates a transfer at Expo station, the current Downtown Line terminus. 

Currently, the MRT is the lowest transport mode from the airport to the city. Taxis, Grab, buses and e-hailing vehicles chaffeur more people to the airport than the MRT system. The Land Transport Authority wants to promote the usage of MRT, and with such an arrangement, it will be inconvenient to change trains so many times just to get to the airport.

Challenges and circumstances regarding the conversion of CGL to TEL. 

1. Different signaling systems, software and hardware

The East West Line currently has 6-car trains while the Thomson East Coast Line has 4-car trains. The signalling system for the East West Line is manufactured by Thales while Alstom is the signalling system manufacturer for Thomson East Coast Line. This will result in a massive change of the train tracks, third rail, electrical equipment as well as the platform screen doors at Tanah Merah, Expo and Changi Airport in order to prepare them for TEL operations. Other countries like Malaysia have also successfully converted a few stations to become part of a different line. In KL, the Kwasa Damansara, Kampung Selamat and Sungai Buloh stations were transferred from the Kajang to the Putrajaya line. Subsequently, in Singapore, the Bukit Batok, Bukit Gombak, Choa Chu Kang and Jurong East stations were converted from the East West Line branch to the North South Line in 1996. But these run on existing and similar signalling systems. The TEL has a completely different set of tools than the EWL.

What complicates the matter is that Changi Airport, the only underground station along the branch, has massive pillars embedded into the platform screen doors' alignment at the airport. This means that if the TEL trains were to line up at the airport, one of the doors will be blocked by the pillar, which may make it inconvenient for persons with disabilities and passengers unfamiliar with Singapore. The only solution to solve the problem will be to take down the pillars after building new ones so that the door problem can be compensated with. 

To add to the challenge, there is a bridge in the airport station which makes it even more difficult for such works. In the worst case, LTA will need to close the airport station for two years just to make such a conversion possible. 

2. Inconvenient loop along the Thomson East Coast Line

The Downtown Line is the only current line designed with a funny loop that intersects itself at the Rochor and Jalan Besar MRT stations. This funny design is the result of three lines being merged together following the collapse of Nicoll Highway in 2004. Downtown Line Stage 1 was planned to be part of the Circle Line Extension, then known as the Downtown Extension, which subsequently lent its name to the Downtown Line. Downtown Line Stage 2, then known as the Bukit Timah Line, was planned to terminate at Nicoll Highway as per the 2001 Concept Plan. Alternately, LTA considered terminating the Thomson East Coast Line Stage 1, 2 and 3 at Nicoll Highway; the Thomson East Coast Line is a merger of the Thomson Line and Eastern Region Line in order to economize plans. The Eastern Region Line was originally planned under the 2001 Concept Plan as a rectangular loop composing Downtown Line Stage 3, and Thomson East Coast Line Stage 4 and 5. These three stages will connect each other at Sungei Bedok MRT station from 2026.

LTA had planned to put an interchange to solve the problem of people navigating the inconvenient loop at the Rochor MRT station. However, they cannot do so as the planned interchange of Downtown Line Stage 2 and 3 for people to bypass the city would be too large, as LTA had also reserved the land at where the interchange was to go for the North South Expressway, now known as North South Corridor, which passes through a large tunnel between Rochor and Jalan Besar. The Bendemeer MRT station was an added additional MRT station in the plans for Downtown Line Stage 3 under the schematic diagram, with an option to add during planning phase. LTA subsequently built said station. Without the interchange at Rochor, it takes a similar duration to walk from Rochor to Jalan Besar as it is to travel along the entire loop between the two stations. 

When the East West Line Changi Airport branch becomes part of the Thomson East Coast Line, there will, of course, be a funny loop, and as such, expect videos made by train enthusiasts on whether it is faster to sit the MRT from Sungei Bedok to Tanah Merah directly on the Thomson East Coast Line, or to sit the Downtown Line from the same station to Expo, and change trains there to reach Tanah Merah. The loop is a result of connecting the CGL and Sungei Bedok stretch to Terminal 5, making the TEL a de-facto airport line. 

This may be convenient for airport passengers and workers, but it may be a hassle for ordinary folks to pass through two airport stations unless the Cross Island Line, planned to connect at Terminal 5 with TEL, is built, so that people can reach other areas such as Pasir Ris or Punggol.