West Ruislip is at the western end of the Central Line and is also served by Chiltern Railways.
The published plans for today, (Emergency Timetable due to weather, 7 January 2010) state that Chiltern Railways will not stop at the station (on the way to London ONLY) but that additional trains will stop at South Ruislip.
This will be a bit of a nuisance for a relatively small number of passengers. However further research makes it a sensible course of action.
The London bound platform at West Ruislip is built in the manner of a passing loop - only trains due to stop there actually use the line - all through trains whizz down the fast middle line.
By removing the need to use the points, a significant risk of mechanical failure is eradicated. Quite sensible really.