There was relief, fear and anger among passengers, including a woman who was nine months pregnant, as they told of explosions, smoke-filled carriages and stumbling along a dimly lit tunnel to escape their crippled train.
The first hint of what was to come happened about 9.15am, two minutes after the train had left Kam Sheung Road Station. The explosion was followed by white smoke, a shower of debris and another bang.
Then the train stopped, the doors opened and passengers were asked to start walking along Tai Lam Tunnel away from the smoke.
Kitty Fong, who is nine months pregnant, was among those who had to make the 2km trek to the next station, Tsuen Wan West.
'It was tiring. I felt like throwing up. But all I could think about was leaving the scene as soon as possible,' Mrs Fong said. 'Luckily, I got help and comfort from a kind-hearted couple. They supported me to prevent me from stumbling in the dim tunnel.'
She was angry at the speed of response of West Rail staff.
'I saw the first West Rail staff coming to help only about 20 minutes after the incident. It could have been very dangerous if someone fell down or collapsed in the tunnel. This is a very serious incident. The government should look into it.'
Another woman said the situation was a mess. 'The driver asked us to run away from the smoke. But we were in the last carriage and we had nowhere to escape.
'It was chaotic. Some people were crying and screaming. Luckily, the carriage was not crowded and passengers could quickly open some windows. Later, the doors were opened.'
One young couple had a Valentine's Day to remember. The 20-year-olds were travelling from Tin Shui Wai to Mei Foo when they heard the blast.
'The explosion was so powerful it nearly sent my boyfriend stumbling,' said Nicole Chiu Yin-ling. 'I was nervous at first, but my boyfriend was with me. Most of the passengers were very calm too.'
It took the couple, who suffered slight hand injuries, half an hour to escape the tunnel.
'It's an unforgettable first Valentine's Day,' Ms Chiu said.