Last time when I was 3g video calling with my friend, there was an LRT train running on the background. I would say, around 300m man. The sound is still can be heard and it is noisy man. She lives near Wangsa Maju LRT station btw.

p.s: I live near Subang airport, last time, there was a hell lots of airplane flying just above my house. dammit, the sound is soooo loud man