my $event = {};

while( <> ) {
    chomp;
    my ( $time, $lane, $factory, $event ) = split " ", $_;

    $event->{ $factory } = {}
        if not exists $event->{ $factory };

    $event->{ $factory }{ $lane } = {}
        if not exists $event->{ $factory }{ $lane };

    $event->{ $factory }{ $lane }{ $time } = $event;
}