Here's a simple program to do what you have described. It is an overkill that it captures all data from the table. But you could do other things with the captured data I suppose. :-)

use strict;
use Data::Dumper;

my @cols = qw/ BUS SERVICE DAY tm FROM DEPT TO ARR 24_7 /;
my @table = ();
my $capture;
while (<DATA>)
{
  chomp;
  $capture=1, next if (/Bus Timetable/);
  $capture=0, last if length($_) == 0 && $capture;
  if ($capture)
  {
    next if /^(?:\| BUS|\+)/; # ignore lines begin with + and BUS
    s/\|//g;    # strip out | characters
    s/^\s+//g;  # strip leading zero's

    my @rec = split /\s+/, $_;
    my %rec = map { $cols[$_] => $rec[$_] } 0 .. $#cols;

    push @table, \%rec;
  }
}

# debug print out
print Dumper(\@table);

# to print out from:to pairs
foreach (@table)
{
  printf "%s%s:%s%s\n", $_->{FROM}, $_->{DEPT}, $_->{TO}, $_->{ARR};
}


__DATA__
---TEXT BEFORE---

+-----------------+
| Train Timetable |
+-----------------+--+------------+-----------+------+
| TRN SERVICE DAY tm | FROM  DEPT | TO    ARR | 24/7 |
+--------------------+------------+-----------+------+
| T4  metro   mon 15 | twn   0900 | Apt  1011 | yes  |
| T6  intl    mon 45 | LDN   1000 | XTR  1426 | no   |
| T2  susx    mon 20 | cly   1034 | btn  1118 | no   |
| T0  xxxxx   xxx xx | xxx   xxxx | xxx  xxxx | xxx  |
+--------------------+------------+-----------+------+

+---------------+
| Bus Timetable |
+---------------+----+------------+-----------+------+
| BUS SERVICE DAY tm | FROM  DEPT | TO    ARR | 24/7 |
+--------------------+------------+-----------+------+
| C4  metro   mon 15 | twn   0900 | Apt  1011 | yes  |
| C6  intl    mon 45 | LDN   1000 | XTR  1426 | no   |
| B2  susx    mon 20 | cly   1034 | btn  1118 | no   |
| A0  xxxxx   xxx xx | xxx   xxxx | xxx  xxxx | xxx  |
+--------------------+------------+-----------+------+

---TEXT AFTER---
[download]

The output is as required -

$VAR1 = [
          {
            'DEPT' => '0900',
            'FROM' => 'twn',
            'ARR' => '1011',
            'DAY' => 'mon',
            'SERVICE' => 'metro',
            '24/7' => 'yes',
            'tm' => '15',
            'TO' => 'Apt',
            'BUS' => 'C4'
          },
...
...

twn0900:Apt1011
LDN1000:XTR1426
cly1034:btn1118
xxxxxxx:xxxxxxx
[download]