I was just in Frankfurt yesterday and the noise is substantial, in the residential neighbourhood I visited it was the main source of noise during the day.
My point was that train lines are millions of miles/km and run through the center of settlements, by design. Almost everywhere in the world, unless you live in a suburb or village, you have a high chance that you will hear trains multiple times a day.
I think there are less people under flight plaths than near trains.
I guess it depends on luck how noisy they can be. I used to get woken every night at 2am by one fucker.
It might be because we are relatively high up (about 100m) and most of the distance between us and the airport is over the sea.
Edit: Just checked on a map and when most aircraft take off from Edinburgh's runway into the prevailing wind they are pointing pretty much directly away from us which might make it more noticeable.
Sometimes it's not possible to avoid climbing over cities because the city ended up engulfing the airport (e.g. Heathrow) - so they will alternate directions to give various towns a break.