<s>
ORCATS	B-Application
(	O
Operational	O
Research	O
Computerised	O
Allocation	O
of	O
Tickets	O
to	O
Services	O
)	O
is	O
a	O
large	O
centralised	O
legacy	B-Device
computer	I-Device
system	I-Device
used	O
on	O
passenger	O
railways	O
in	O
Great	O
Britain	O
.	O
</s>
