I was working on St. Pancras in about 2005 or so... for Palmers.
They was building/repairing the Barlow Shed part of the station.
Anyway, at each end they had 2 Hangers, that spanned the entire width of the roof and i was passing the Boards up from the bottom Lift up to the next lift - nothing special, just normal work.
I dunno why, but i must have had a blonde moment and lost my concentration and as i passed up one of the last Boards i stepped back a bit too far and i felt a slight drop where i stood... i turned round and saw that id stepped completely off the back of the Board and onto the unboarded Tranny behind me.
An inch either way and id have fallen about 80ft straight onto a load of razor sharp Reebar... id be dead.
Lucky i was that day. Now i try to be more careful when i work, lol.