Rail transport in Singapore
Rail transport in Singapore mainly consists of a passenger urban rail transit system spanning the entire city-state: a rapid transit system collectively known as the Mass Rapid Transit (MRT) system operated by the two biggest public transport operators SMRT Trains (SMRT Corporation) and SBS Transit, as well as several Light Rail Transit (LRT) lines also operated by both companies. In addition, local specialised light rail lines are in operation in places such as the Singapore Changi Airport and Sentosa.
A short remaining section of the railway originally built during the British colonial period is connected to the Malaysian rail network, and is operated by Malaysian railway company Keretapi Tanah Melayu (KTM). The Singapore section of the railway now serves only inter-city passenger services; until 2011 the railway also carried freight between Malaysia and the Port of Singapore at Tanjong Pagar. Two other international rail connections are currently planned: the Kuala Lumpur-Singapore High Speed Rail and the Johor Bahru-Singapore Rapid Transit System.
Local Urban Rail Network

a.    Mass Rapid Transit (MRT)
Singapore's public transport system has been reliant largely on buses, until the opening of the first section of the Mass Rapid Transit in 1987. Although buses still enjoy an average daily ridership exceeding twice the number carried on both the MRT and LRT systems (2.8 million on buses, compared to 1.3 million on the MRT and LRT in the year 2004), the Land Transport Authority plans to expand the rail system such that buses will eventually play only a feeder role to an extensive rail network.
The current MRT network consists of five main lines, for a total network length of 153.2 km (95.19 mi) and with 104 stations. The North South Line, East West Line and Circle Line are operated by SMRT Trains (SMRT Corporation), while the North East Line and Downtown Line since 22 December 2013 are run by SBS Transit. The Circle Line Extension from Promenade to Marina Bay began operation since 14 January 2012.

b.    Light Rail Transit (LRT)
Singapore has had various forms of light urban rail systems, such as the monorail system on Sentosa island, which opened in February 1982. This 6.4 km, 6-station system was closed in March 2005 and a new Sentosa Express system was built by December 2006. The Changi Skytrain, a people mover system shuttling passengers between the three terminals at the Singapore Changi Airport, was opened originally in 1990 along with Terminal 2 and upgraded in 2006 with the completion of Terminal 3. The Jurong BirdPark previously featured an air-conditioned panorail which closed in 2012.
Light rail transit functioning as feeders to the main MRT network has been under study for some time, particularly since the existing urban configuration of self-containing new towns spread out in the suburbs meant it was feasible to consider having light rail systems connecting each town to the MRT station in the town centre, a role which has traditionally been provided by feeder buses. Thus, the first SMRT Light Rail (SMRT Corporation) operated LRT was opened in Bukit Panjang in 1999 to provide a connection to Choa Chu Kang in neighbouring Choa Chu Kang New Town. Although subsequently hit by over 50 incidents, some of which resulted in several days of system suspension, similar systems albeit from a different company were introduced in Sengkang and Punggol in 2003 and 2005 respectively, both operated by SBS Transit.
International Rail Links
a.    KTM West Coast Line
The sole mainline railway line providing direct international connections is operated by Keretapi Tanah Melayu or Malayan Railway, with services formerly commencing from the Tanjong Pagar railway station in southern Singapore. The present single track line is 1 (formerly 36.8) km long, with a gauge of 1000 mm, and had proceeded north through Bukit Timah, before crossing the 1.2 km causeway to Johor Bahru on the Malay Peninsula, where it then runs along the peninsula's west coast through Kuala Lumpur and onwards to Thailand and beyond.
A railway system dating back to the British colonial era, it is now considered inadequate in meeting contemporary transport requirements. Both goods and passengers would have originally arrived by ship and hence the railway terminates at Tanjong Pagar, where port operations are still concentrated. There was similarly a branch line which leads to the Jurong industrial area, but which has since been expunged. The development of an efficient transport network in Singapore, and the containerisation of maritime trade globally meant that the existing rail system no longer played a significant part in the ferrying of goods, and is now catered primarily for passenger transport.
Over time, however, the rail service was once again unable to compete effectively with modernising modes of alternative transport. The high frequency of air shuttle services between Singapore and Kuala Lumpur presented a much faster and more comfortable means of transport despite the high prices. From February 2008, partial deregulation of air travel between Singapore and Kuala Lumpur was introduced, and with full deregulation from December 2008 air fares are currently (April 2009) relatively low. However, the convenience of air travel should not be overestimated; typical time from Kuala Lumpur Sentral Station to City Centre of Singapore (via the low cost terminals at each airport) is around five hours. Moreover, the opening of the North-South Expressway in Malaysia from the late 1980s drastically cut travel time by private car or coaches to around five to five-and-a-half hours from Singapore to Kuala Lumpur.
In the light of this, the Malaysian government is currently undertaking plans to upgrade the railway system to an electrified, double-tracked and express line, but it will not be extended to Singapore.
As a result of the agreements leading up to the independence of Singapore, the land on which the railway ran on was owned by KTM, and would remain so as long as the rail system was in operation. This arrangement had erupted into several spates of diplomatic disputes between the two countries. Land-scarce Singapore was keen to move the railway station to either Woodlands or Kranji, thus freeing up large tracts of land for redevelopment. In return, the Singaporean government was willing to offer a plot of prime land in the Marina Bay area for development by the Malaysians, although this concession was not required according to the original agreements. The negotiations were stalled, however, when the Malaysians were unimpressed with the compensation amount, and expressed concern over accessibility should the railway station be moved further from the city centre. Resolution was reached in May 2010 with the agreements endorsed on June 2011. From 1 July 2011, the only KTM railway terminal and station in Singapore is the Woodlands Train Checkpoint.
b.    Kuala Lumpur-Singapore High Speed Rail
Plans to build a high-speed rail link between Singapore and Kuala Lumpur have been mooted in recent years. A proposal was brought up in 2006 by YTL Corporation Berhad, builder and operator of the Express Rail Link in Kuala Lumpur, however it was not further acted upon due to the Malaysian government's lack of interest at that time.
In 2013, the governments of Singapore and Malaysia officially agreed to build the Kuala Lumpur–Singapore High Speed Rail between Kuala Lumpur and Singapore by 2020 at a meeting between Singapore’s Prime Minister Lee Hsien Loong and Malaysia’s Prime Minister Najib Razak in Singapore. The high-speed rail link will cut travel time between the two cities from seven hours on existing rail lines, to about 90 minutes. Malaysia's Land Public Transport Commission chairman, Syed Hamid Albar, announced the stops in Malaysia for the high speed railway. The seven stops are namely, Kuala Lumpur, Putrajaya, Seremban, Ayer Keroh, Muar, Batu Pahat and Nusajaya. The Singapore government proposed three possible sites for the Singapore station: Tuas West, Jurong East or the Downtown Core. In May 2015, it is announced that Jurong East is chosen as the HSR terminus in Singapore, 600 metres away from the current Jurong East MRT station. The construction of the railway is expected to start in late 2016.
c.    Johor Bahru-Singapore Rapid Transit System
The idea of an MRT link across the border to Johor Bahru has been mooted since the first MRT line was built in the 1980s. In 2010 when the relocation of the KTM terminus to Woodlands was agreed, it was also announced that a rapid transit system would be built to enhance connectivity across the border and to relieve congestion on the Johor-Singapore Causeway.
The RTS is currently envisioned as a two-station line. Singapore RTS terminus will be at Woodlands North, providing interchange with the upcoming Thomson-East Coast MRT Line. The Johor Bahru RTS terminus will be at Bukit Chagar, next to Johor Bahru Sentral railway station and Sultan Iskandar CIQ Building. The two stations will each have combined Customs, Immigration and Quarantine (CIQ) facilities of both countries, similar to the current arrangement at Woodlands Train Checkpoint. Passengers will clear both countries' border controls before boarding the RTS train, and need no further checks upon arrival at the other station.
After the completion of the RTS link, the KTM terminus may be relocated to Johor, completing KTM's withdrawal from Singapore.