Will the br 420 also being layerd in other routes, like koln to aachen? since we will get a timetable update for that.
There's an issue of anachronism/route-era appropriateness. The 420 is a very old EMU. They would all be gone by now except Munich decided to buy the ones Stuttgart was getting rid of and recondition them (so the Munich variant wouldn't be appropriate anywhere else). Stuttgart itself retired them in 2016; the Frankfurt/Rhein-Main trains were withdrawn in 2014 although they have kept some in reserve as emergency replacement trains. They once also ran on the VVRR around Dusseldorf, but were replaced years ago. To the best of my knowledge Cologne kept theirs the longest, but I don't recall if they were running the westbound S12/S19 services. EDIT: Yes, until just last year Cologne ran the S12 with 420s, so they would fit there (although the VVRM markings would be wrong)
Normally, newer stock won't be automatically layered into older timetables. Since the SKA timetable is WIP as much as the 420 is, I can indeed imagine that there will be a 420 layer. Other than that, I wouldn't expect it on other routes. Substitution won't work as well, because the substitution logic requires equal amount of coaches. As the BR 422 and 423 have 4 coaches, but the 420 only has 3, I won't work.
