I agree with those that the guy on left is Heer (eagle, collar patches). I think the guy on the right is political - the collar tabs look like Kreisleitung and the cap matches.
This is a letter I have received from Berlin regarding my the gentleman on the right I know this was during the First World War. But could it explain his uniform.
That's what I thought too, he could be Reichsbahn employee. Had a look here . Reichsbahn Headgear See the post with Weimar era rank chart . 1 & 2 look like what our chap has . Could be transitional period before going full Third Reich. Ah, good point. Ruins mine about the Reichsbahn Just looked up a rank chart. http://images-mediawiki-sites.thefullwiki.org/00/1/9/7/58302642863568170.jpg