<s>
A	O
platform	B-Application
display	I-Application
,	O
destination	B-General_Concept
display	I-General_Concept
or	O
train	B-Application
describer	I-Application
(	O
British	O
English	O
)	O
is	O
supplementing	O
the	O
destination	B-General_Concept
sign	I-General_Concept
on	O
arriving	O
trains	O
giving	O
passengers	O
an	O
advance	O
information	O
.	O
</s>
<s>
In	O
later	O
usage	O
they	O
were	O
replaced	O
by	O
passenger	B-Application
information	I-Application
display	I-Application
systems	I-Application
(	O
PIDS	O
)	O
allowing	O
for	O
real-time	B-General_Concept
passenger	B-Application
information	I-Application
.	O
</s>
<s>
The	O
first	O
railway	O
stations	O
had	O
only	O
a	O
time	O
table	O
for	O
passenger	B-Application
information	I-Application
.	O
</s>
<s>
The	O
train	O
handling	O
became	O
optimized	O
to	O
allow	O
for	O
less	O
than	O
a	O
minute	O
from	O
arrival	O
to	O
departure	O
at	O
a	O
stop	O
which	O
triggered	O
the	O
usage	O
of	O
loudspeakers	O
and	O
platform	B-Application
displays	I-Application
.	O
</s>
<s>
A	O
train	B-Application
describer	I-Application
is	O
originally	O
an	O
additional	O
apparatus	O
at	O
British	O
railways	O
that	O
ensures	O
that	O
the	O
identity	O
of	O
each	O
train	O
is	O
displayed	O
on	O
the	O
signalbox	O
panel	O
together	O
with	O
the	O
indication	O
of	O
that	O
train	O
's	O
presence	O
,	O
usually	O
offering	O
routing	O
information	O
.	O
</s>
<s>
This	O
routing	O
information	O
would	O
then	O
be	O
passed	O
through	O
to	O
the	O
platform	B-Application
display	I-Application
for	O
passenger	B-Application
information	I-Application
.	O
</s>
<s>
A	O
series	O
of	O
interconnected	O
signal	O
boxes	O
form	O
a	O
train	B-Application
describer	I-Application
system	O
(	O
TDS	O
)	O
transferring	O
train	B-Application
describer	I-Application
data	O
to	O
be	O
shown	O
on	O
the	O
respective	O
signalbox	O
panel	O
in	O
a	O
train	B-Application
describer	I-Application
display	O
.	O
</s>
<s>
In	O
a	O
centralized	O
electronic	O
interlocking	O
the	O
current	O
train	O
location	O
and	O
identification	O
is	O
used	O
to	O
predict	O
the	O
arrival	O
at	O
the	O
next	O
stop	O
allowing	O
for	O
countdown	O
clocks	O
for	O
passenger	B-Application
information	I-Application
.	O
</s>
<s>
The	O
term	O
passenger	B-Application
information	I-Application
display	O
has	O
widely	O
replaced	O
the	O
term	O
platform	B-Application
display	I-Application
as	O
station	O
design	O
can	O
include	O
different	O
types	O
of	O
information	O
displays	O
-	O
like	O
a	O
departure	O
board	O
in	O
the	O
main	O
hall	O
,	O
a	O
shorter	O
list	O
in	O
the	O
tunnels	O
and	O
an	O
announcement	O
of	O
the	O
next	O
train	O
on	O
each	O
platform	O
side	O
-	O
which	O
all	O
get	O
their	O
information	O
from	O
a	O
central	O
electronic	O
railway	O
control	O
system	O
.	O
</s>
<s>
Additionally	O
passenger	B-Application
information	I-Application
displays	O
have	O
come	O
into	O
use	O
for	O
bus	O
and	O
tram	O
stops	O
as	O
well	O
where	O
the	O
destination	B-General_Concept
display	I-General_Concept
equipment	O
is	O
technically	O
similar	O
.	O
</s>
