On Sun, 17 Aug 2008 08:04:26 -0700 (PDT), M J Forbes wrote:

For some reason WCML Desiros use "Special" on the ends when "Not in
service" is selected for the side.

Assuming that the PIS on the 350s is the same as SWTs 444/450s, the
driver/guard is able to display whatever they want (I've noticed a few
450s with "Happy Christmas" on the side displays in the past!).
Obviously, the system is pre-programmed with 'regular' displays, but
this can be overridden with a few taps on the keypad.

As (AFAIK) the displays on the cabs cannot scroll, and "Not in
service" won't fit on the matrix, perhaps this is LM's reason for
electing to use "Special", as opposed to "Depot" on the south-of-the-
Thames Desiros.

SWT Desiros display "Not in use" on the cabs.