There are no plans to deploy Singapore Armed Forces (SAF) troops to respond to massive train breakdowns, the Defence Ministry said yesterday.

The Land Transport Authority (LTA) had approached the SAF in 2015 to explore the idea of deploying army personnel during large-scale disruptions for crowd control, a move The Straits Times reported then.

Mindef had said it would work with the LTA.

Those plans never took off. A Mindef spokesman told The Straits Times yesterday that SAF resources have not been deployed thus far for rail disruptions, and the LTA and operators remain the first line of responders during breakdowns.

She said the SAF may be called upon to assist other government agencies during "extreme circumstances", such as the Sars crisis in 2003 and a period of thick haze in 2013.

Even during such situations, the SAF ensures its ability to safeguard Singapore is not compromised, she added.

Defence analyst Ho Shu Huang of the S. Rajaratnam School of International Studies felt Mindef was clarifying its role of focusing more on security issues.

Said Mr Ho: "In a way, this is a return to (SAF's) core competencies and what it trains for - the organised and managed use of violence to defend Singapore."

He noted that the talks with LTA in 2015 took place before a wave of terror attacks in major cities and the launch of the SGSecure movement in 2016.

"The SAF probably is kept busy preparing for a wider range of security scenarios and it is indeed prudent not to spread the organisation too thinly," he added.

But tapping on grassroots volunteers is "a clever alternative" as the skills they pick up from responding to rail disruptions could be useful in other national emergencies, he said. This would feed nicely into the SGSecure movement and, more broadly, the civil defence pillar of Total Defence, he said.