On Sun, 5 Apr 2009 00:29:09 +0100, Recliner wrote:

Does this sort of thing happen often, and what could have made it
necessary? Or did someone make a mistake?

I once experienced something similar on the Met. I was on a fast
eastbound train that stopped (as usual) in platform 6 at
Harrow-on-the-Hill. But as we pulled out of the station, to my
surprise, we took the crossover to the slow line. However, we still
didn't stop at the intermediate stations (and we certainly didn't slow
to 5mph for the starter signals, either).