A train in Pakistan. Photo credit to China Daily. Singapore can achieve this in 2030. This is a picture of future Singapore.
Look at the picture carefully. Look at how the steel plates folded, outwards and upwards. It looks like the explosion was from inside or from below. An internal accidental, hitting a mine below?
If it was hit by a torpedo, the steel plates would be folding outwards from one side. You make your conclusion.