hafas-m(1): VRN is a relatively suitable DB HAFAS replacement

=over

=item * DB HAFAS is no more. At this point, there is no suitable HAFAS instance

that covers local and regional / long-distance transit in Germany.

=item * HAFAS does not provide real-time data for routes of stationboard

entries.  Hence, B<--via> estimates the arrival time from scheduled

departure and departure delay