Security on the Mass Rapid Transit (Singapore)
The overall security concerns of the Mass Rapid Transit system in Singapore related to crime and terrorism are not high on the agenda of the system's planners since its inception . For instance, there was no physical police presence in the rail system, and nor were private security guards deployed. CCTV systems were not widely used, and there were no passenger service booths on the platform level, the only manned booth being the one at the station control room. These measures were not necessary, however, as incidents of crime rarely occurred on the rail system.
In the wake of heightened security concerns as a result of the September 11, 2001 attacks, and also particularly the 11 March 2004 Madrid attacks in which the commuter rail system was targeted, the Singapore government initiated several measures aimed at securing the rail system from a similar attack. In the months immediately after the Madrid attacks, the two rail operators, SMRT Corporation and SBS Transit, started employing private unarmed guards who patrol the station platforms, and are empowered to check the belongings of commuters. The Singapore Police Force announced that regular police officers may commence patrolling duties within stations and trains, although this was not visibly apparent except in the immediate period after announcements were made.
In reaction to a second major terrorist attack on a public transport system in the 7 July 2005 London bombings, the police deployed armed Police Tactical Unit officers to patrol within stations the day after the bombings occurred, while pre-existing security measures were placed on higher alert. 
On 14 April 2005, the Singapore Police Force made a public announcement on its plans to step-up rail security  by establishing a new specialised then known as the Police MRT Unit. These armed officers began visible patrols on the MRT and LRT systems  on 15 August 2005, conducting random patrols in pairs in and around rail stations and within trains. Dressed in tactical uniforms similar to members from the Police Tactical Unit, they are however differentiated by blue-coloured berets, and are armed with less firepower with each officer carrying a Taurus Model 85 revolver and T-baton similar to officers from Neighbourhood Police Centres.  These officers are trained and authorised to utilise their firearms based on the officers' discretion, including "shoot to kill" if deemed necessary. On 15 August 2009, the unit was established as an independent unit known as the Public Transport Security Command.
Closed Circuit Television (CCTV)
Plans were also announced in fixing CCTVs within trains operated by SMRT Corporation, in line with existing fixtures in SBS Transit trains. These measures were deemed necessary in light of the timing of the attacks which took place while the 117th IOC Session was still in progress in the city, and that the meeting venue at Raffles City was located beside City Hall MRT Station, a major interchange station with very high passenger traffic.
Announcements & notices
"Attention please, please do not leave your belongings unattended. If you see any suspicious-looking person or article, please inform our staff."/"If you see any suspicious-looking person or article, please inform our staff or press the emergency communication button located at the side of the train doors."
- Recorded audio announcements such as the above played in stations & trains respectively, notices on plasma display screens on station platforms and in train carriages, as well as posters and notices in stations remind commuters to report instances of unattended packages and other suspicious activities to the authorities.
Trash bins & mail boxes
This precautionary measure has been taken to safeguard Singapore MRT stations.
Exercise Northstar V
On 8 January 2006, a major civil exercise, codenamed Exercise Northstar V and simulating bombing and chemical attacks at Dhoby Ghaut, Toa Payoh, Raffles Place and Marina Bay MRT stations was conducted. Thirteen affected stations were closed during the three-hour duration of the exercise, affecting about 3,400 commuters .
- ^ López, M.J.J. (1996), Den Haag: RCM-advies, "Crime Prevention Guidelines for the Construction & Management of Metro Systems", pg. 35-39.