do not show direction for winged wagons with different normalization needs

				# and invert the direction passed on to $wref if it is not

				# the wagon with the lowest wagon number.

				my @wagons = $wr->wagons;

				# Note that we need to check both the first two and the last two

				# wagons as the train may consist of several wings. If their

				# order differs, we do not show a direction, as we do not

				# handle that case yet.

				# skip first wagon as it may be a locomotive

				my $wn1 = $wagons[1]->number;

				my $wn2 = $wagons[2]->number;

				my $wp1 = $wagons[1]{position}{start_percent};

				my $wp2 = $wagons[2]{position}{start_percent};

				my @wagons = $wr->wagons;

				if ( $wn1 =~ m{^\d+$} and $wn2 =~ m{^\d+$} ) {

				# skip first/last wagon as it may be a locomotive

				my $wna1 = $wagons[1]->number;

				my $wna2 = $wagons[2]->number;

				my $wnb1 = $wagons[-3]->number;

				my $wnb2 = $wagons[-2]->number;

				my $wpa1 = $wagons[1]{position}{start_percent};

				my $wpa2 = $wagons[2]{position}{start_percent};

				my $wpb1 = $wagons[-3]{position}{start_percent};

				my $wpb2 = $wagons[-2]{position}{start_percent};

				if (    $wna1 =~ m{^\d+$}

					and $wna2 =~ m{^\d+$}

					and $wnb1 =~ m{^\d+$}

					and $wnb2 =~ m{^\d+$} )

				{

                   # We need to perform normalization in two cases:

                   # * wagon 1 is leftmost and its number is higher than wagon 2

                   # * wagon 1 is rightmost and its number is lower than wagon 2

                   #   (-> the leftmost wagon has the highest number)

					if (   ( $wp1 < $wp2 and $wn1 > $wn2 )

						or ( $wp1 > $wp2 and $wn1 < $wn2 ) )

					# However, if wpa/wna und wpb/wnb do not match, we have a

					# winged train with different normalization requirements

					# in its wings. We do not handle that case yet.

					if ( ( $wna1 <=> $wna2 ) != ( $wnb1 <=> $wnb2 ) ) {

						# unhandled. Do not set $wref->{d}.

					}

					elsif (( $wpa1 < $wpa2 and $wna1 > $wna2 )

						or ( $wpa1 > $wpa2 and $wna1 < $wna2 ) )

					{

						# perform normalization

						$wref->{d} = 100 - $wr->direction;

					}

					else {

						# no normalization required

						$wref->{d} = $wr->direction;

					}

				}