The Falmouth branch seems to have had two 153s for the last week so a good thing in this case as one unit could be detached to keep the service going..
I suppose this will be the way forward when the Penryn passing loop is commissioned later in the year. Single 153s on the half hourly service then joining up for the hourly service and return to base at PNZ.
The current plan for the enhanced Falmouth service can be found in the link below.
http://www.firstgreatwestern.info/coffeeshop/index.php?topic=2940.msg22433#msg22433I believe that a pair of 153s are now diagrammed on the Falmouth branch - certainly on weekdays
FGW Class 153 diagrams can be found in the link below.
http://www.southwesternlines.co.uk/downloads/fgwdiagmay08/SX_PM153s.pdf