John Sandy: "After 20 or 30 seconds of getting into the tunnel from King's Cross, I heard an almighty bang and the train came to a very, very sudden stop. The carriage was thrown into darkness - there was lots of soot and ash.
"We could hear screaming further down the carriage and it was getting a lot hotter. There was an initial fear of fire...
"Later on that day it was quite odd to see myself on telly coming out of King's Cross with the other survivors.
"This was something that happened to everyday people, not politicians, not soldiers, not people on the front line. This was something that happened to people that were going about their everyday business."
Watch John's story on More4 News.