Add TO_JSON function

	return $self->{errstr};

}

sub TO_JSON {

	my ($self) = @_;

	# ensure that all objects are available

	$self->direction;

	$self->origins;

	$self->destinations;

	$self->train_numbers;

	$self->train_descriptions;

	$self->wagons;

	$self->{platform} = $self->platform;

	my %copy = %{$self};

	delete $copy{from_json};

	return {%copy};

}

sub direction {

	my ($self) = @_;