On Thu, 05 Jul 2007 06:31:25 -0700, Boltar
wrote:

On 5 Jul, 14:09, "Recliner" wrote:
Am I right in thinking that 1992 stock has smaller wheels than other
Tube trains and is perhaps more likely to derail when it encounters
something on the track?

It does seem strange that a heavy train could become derailed by
something light enough to have become dislodged by vibration or air
movements and apparently flap around in the wind.

Maybe, but a train has considerable forward momentum so wouldn't take
too much to derail if the obstruction was in exactly the right (or
wrong, perhaps) position.