1.   Thirty others were injured, one seriously, when at least three carriages overturned, Hertfordshire police said.

2.   Two carriages overturned and late Friday it was still unclear whether anyone was trapped under them.

3.   Two carriages overturned and another five ran off the tracks.

4.   Two carriages overturned.

5.   Four carriages overturned and caught fire, killing four passengers on the spot.

6.   No carriages overturned in the accident.