Opportunity to build on a plot of land next to the suburban railway line?

I consider the noise level negligible, given that the circumstances are appropriately taken into account. I currently live in a new apartment on the first floor about 150 meters from a station with freight traffic. With proper triple-glazed windows, etc., I really don't hear anything from the trains – not even at night. What I do hear, however, are my neighbors, who seemingly live on the balcony... As some before me have said: There are so many other noise sources that are far more disturbing. Therefore, for me, the advantages clearly outweigh the disadvantages in your situation. Had I foreseen the situation with the neighbors, I would have built directly in my cul-de-sac instead of renting again...

If a development area is going to be designated there anyway, the likelihood that the municipality will build a noise protection fence is not exactly low. Have you inquired about that? Definitely do it! Because that changes the noise situation completely. The sound virtually "spills" over this noise protection fence and that should be taken into account in the planning. Because where it "spills over" it is uncomfortably loud and that should not be right at the bedroom window. So ask if and then how, how high etc. and take that to the planning meeting with the architect.

Personally, a train every 8 minutes would be unpleasant for me, but I really can't assess the real situation.

I would also ask db if anything is planned regarding the route. You wouldn't want to build there and then have the line expanded for freight traffic three years later. As far as I know, db does provide information on that.

If everything else fits: go for it! I personally find it less disturbing when I'm sitting on the terrace and a train passes by now and then than when I have the noise present in the bedroom.

Next door my neighbors have visitors with many children and many adults. They went outside with their food. There is nothing worse than noisy neighbors

Sorry, but that drives me crazy! Your neighbors have visitors with children, there is romping, laughing, and maybe the grill is on. They are sitting outside, talking, laughing, the children are happy. Really a drama! And on a Saturday! Is it really that terrible? Is it every day? Continuously? Or they just occasionally have visitors and enjoy life?

I think these are the normal neighborly "emissions" you just have. And one should not forget: you also keep being one of the emitters yourself again and again! It’s a give and take. Especially in summer, a lot of life also happens outside. And even after 10 p.m., when it finally cools down and becomes pleasant. That sometimes also involves noise. When we’re on vacation in the south, we find it charming, sitting outside ourselves until late at night, laughing, drinking wine, and enjoying the mild summer nights. But woe to the neighbor if he ever does that!

I would never dream of getting upset about neighbors who occasionally have visitors and throw a party and it gets a bit louder. If my neighbor with her husband sits on the balcony, drinks a little wine, and talks with him, I hear that when I’m lying in my bedroom—even though there is a street in between. This happens on the few, very mild summer nights, so not on more than 300 nights a year. If I want to sleep in such a night instead of sitting outside myself, I can either shut my window (thanks to controlled residential ventilation, not a problem) or leave it open and put earplugs in (my preferred solution).

If the other neighbor grills, I smell it—it lasts a maximum of 1 hour, then it’s over. And that also happens less than 60 days a year.

If all that bothers me so much, then unfortunately I am in the wrong place in a normal residential area. Then I recommend the Einsiedlerhof, the nursing home, the sanatorium, or an apartment, a house in a spa area with special quiet requirements.

Please don’t get me wrong: if someone has a party every day, is loud until late at night, blasts me daily with heavy metal, that is certainly no longer acceptable and I should defend myself there. But if someone occasionally has visitors, it gets a bit louder ONCE IN A WHILE, children romp and it lasts a bit longer in the evening, you can definitely turn a blind eye. As I said: that can also happen the other way around. Especially in a summer when certainly many families, due to the current situation, are spending their summer vacation at home in the garden and cannot go anywhere to the sea. Please keep things in perspective!

, at least my post regarding noisy neighbors was more about the fact that there are more sources of noise than the railway line and that the trains shouldn't necessarily be overestimated.

Because no matter how socially acceptable it is to use your garden, it simply makes noise. How one evaluates it is another matter, but the existence of the noise cannot be disputed.
Moreover, these sounds often occur exactly at the time when you yourself want to enjoy the peace in the hammock, because everyone has finished work and is at home.
Of course, that’s okay. But at least with some neighbors, you often wouldn’t even be able to notice a train under the drone of the lawnmower.

Advantage: Mowing the lawn is prohibited on Sundays, taking the S-Bahn is not.

Advantage: Mowing the lawn is forbidden on Sundays, taking the S-Bahn is not.

As if that really bothers anyone in the village ops:

In Berlin there is a residential building where the U1 runs through (located at Bülowbogen at Gleisdreieck). If something like that is possible and people really live there, an S-Bahn at a distance of 10-15m should probably also be possible. But it always depends on personal sensitivity. As a noise-sensitive person, I would probably rule that out. But the tip with camping is probably really the best...