27-11-2023: New picture: Fox den.

As I said before: I did not copy anything from the real world.
I bought the stations because I liked them. Gave the cities and villages the name of the station and that's all. So don't expect to find a copy of the named cities.

After leaving the station of Baden Baden the train turns to the right and dives into a tunnel, rolls down to the lowest level (50 cm lower) and stops in the hidden station (nine tracks). An other train takes over.
Still on the lowest level, the train leaves the tunnel on the other side of the lay-out, passes a farm and disappears in a tunnel, climbs in the tunnel (spiral/helix) to the station of Bonn, back to the starting point.

Most of the passenger trains have interior lights. I use conducting couplers, so I need only one pick-up shoe for a consist or the locomotive provides the necessary current. Even if the wagons are not prepared for conducting couplers, you can find a way to realise that. Amongst others I modified a passengertrain with 7 4-axle Württemberger wagons that way.
Instead of the standard Märklin bars I started to use the RTS conducting short couplers, now I use mostly the conducting Märklin short couplers (the RTS model).
Pictures of the modification

For a long time no passengers were on the passengertrains. When I bought the DB Type BC4i-33 Compartment Cars I decided to add passengers to the cars. It makes the trains look more real.
Sometimes you need to cut off the legs (or buy without legs), otherwise it is impossible to place the passengers opposite an other passenger. You won't notice the cut off legs.
You need a lot of "Preiserlein" to populate a train. If you have a consist of let's say five wagons, with fifty passengers you only have ten persons in a wagon. That doesn't look crowded. So try to find the cheaper ones. I use figures made by Preiser, Faller, Fleischmann and others sold in the larger packages. But I don't like the very cheap ones with a shiny face and hardly no facial expression.