Noise subway near building house

Hi all,
A friend of mine has a plan to buy a apartment near subway. But in Vietnam, this is the first subway. We do not know is it noisy or vibrate ? I read some forum about it, they told if living on the fourth floor, the noise will be reduced. If you lived near subway, could you tell me about it?
Thanks,

there is a first for everything in Vietnam. if you're worried about the risk, go with your gut instinct rather than wait for the I told you so moment.

Go buy elsewhere just to save any problems.

Thank you so much.We are thinking about it.