Actually tram engines had been phased out between 1910 and 1915 . Replacement was
Mecklenburg T 7 (DRG Class 99.30). In 1923 Mecklenburg T 42 (DR 99.31) had been added.
Engines in use today are are DR 99.32 and had been on this line since 1932 (the year Hitler became Chancellor)
There is also a new 99.32 in use which has been build in 2008 using old plans.