A reply to the original (prefork) version.

grt.pl

use Data::Dumper;

my @files = (
    map(      "/data/switch/cdr/SWITCH_20130627_151${_}00", qw( 8 5 9 7 6 ) ),
    map( "/data/switch/otherCDR/SWITCH_20130627_151${_}00", qw( 9 6 8 5 7 ) ),
);

print Dumper \@files;

my @sorted =
    map  { unpack 'x[N] a*' }
    sort
    map  { /SWITCH_\d{8}_(\d{6})/ or die; pack 'N a*', $1, $_ }
    @files;

print Dumper \@sorted;

grt6.p6

use v6;
my @files =
    <8 5 9 7 6>.map({     "/data/switch/cdr/SWITCH_20130627_151{$_}00"}),
    <9 6 8 5 7>.map({"/data/switch/otherCDR/SWITCH_20130627_151{$_}00"});

say @files.perl;

my @sorted = @files.sort({ / SWITCH _ \d**8 _ (\d**6) / or die; $0; });

say @sorted.perl;

Notes

1. Spelling corrected: Schwartzian transform
2. No need to use parens around \d{8}.
3. I like ST better, but GRT is faster for large lists:
    http://www.perlmonks.org/?node_id=145659
4. Need to warn or die to show bad data when regex fails.
5. Perl 6 automatically does ST for you:
    my @sorted = @files.sort({ / SWITCH _ \d**8 _ (\d**6) / or die; $0; });

output

$ ./grt.pl # Same output as ST version
$VAR1 = [
          '/data/switch/cdr/SWITCH_20130627_151800',
          '/data/switch/cdr/SWITCH_20130627_151500',
          '/data/switch/cdr/SWITCH_20130627_151900',
          '/data/switch/cdr/SWITCH_20130627_151700',
          '/data/switch/cdr/SWITCH_20130627_151600',
          '/data/switch/otherCDR/SWITCH_20130627_151900',
          '/data/switch/otherCDR/SWITCH_20130627_151600',
          '/data/switch/otherCDR/SWITCH_20130627_151800',
          '/data/switch/otherCDR/SWITCH_20130627_151500',
          '/data/switch/otherCDR/SWITCH_20130627_151700'
        ];
$VAR1 = [
          '/data/switch/cdr/SWITCH_20130627_151500',
          '/data/switch/otherCDR/SWITCH_20130627_151500',
          '/data/switch/cdr/SWITCH_20130627_151600',
          '/data/switch/otherCDR/SWITCH_20130627_151600',
          '/data/switch/cdr/SWITCH_20130627_151700',
          '/data/switch/otherCDR/SWITCH_20130627_151700',
          '/data/switch/cdr/SWITCH_20130627_151800',
          '/data/switch/otherCDR/SWITCH_20130627_151800',
          '/data/switch/cdr/SWITCH_20130627_151900',
          '/data/switch/otherCDR/SWITCH_20130627_151900'
        ];