I think senior transport correspondent Christopher Tan was not seeing the wood for the trees when he argued that being stuck on a crawling train would be less preferable than seeking alternative transport (MRT disruption: Go slow or shut down to fix problem?; Sept 21).

It is better to continue travelling in a slow train rather than to walk out to take crowded buses.

I believe the operator SMRT took the right approach to keep trains running at a slow speed in order to check the whole system in dynamic mode and spot potential troubles.

Perhaps SMRT could have run the trains at half the speed to improve travel time instead of managing operations at one-fifth the speed.

It is inevitable that commuters suffer some inconveniences, but a slow-moving train would enable engineers to fix the identified problem as well as check related components and sub-modules in the complete system to spot unexpected deterioration or misalignment and prevent future occurrences.

The job is more onerous and taxing when trains are running but it is far better to spot potential troubles in dynamic mode.

When systems are at rest, in stationary mode or completely broken down conditions, engineers cannot identify potential troubles.

That is why sophisticated cars are completely checked by instruments in vehicle inspection centres to prevent failures while the engines are kept running.

In dynamic mode, every component, signal gadget and module in the complete system must be working in harmony to enable moving trains to function as designed.

This diagnostic approach, with trains running at slow speeds where possible, is technically correct to prevent repeat or similar disruptions and enable future smooth-running trains with maximum uptime.

Paul Chan Poh Hoi