Even more freaky is the reason for doing this: Over the past years, DB and RDC have been fighting over track usage rights on the line to Sylt to operate the highly profitable autorack trains.
Normally, if two companies want to run equal trains, the available slots are divided equally as well.
Now DB came up with this brilliant idea: By coupling a DMU at the end, uncoupling it on the mainland in Niebüll and letting it run further to Bredstedt, DB's line it technically 20 kilometers longer and as the regulatory body prioritizes longer lines, this gives the DB more slots.
With all the shunting, the so-called Sylt Shuttle Plus takes about 20 minutes longer than the normal regional trains, so they run practically empty.
RDC meanwhile only got a handful of slots, though they currently lack rolling stock anyway.