you have an electric train travelling at 50 miles an hour in a southerly direction?

the wind is blowing at 70 miles an hour in a northerly direction, which direction would the smoke from the train be travelling,

There's no smoke; it's ELECTRIC!

An electric train does NOT produce smoke.

it would just dissapear

thats a bit of an old chestnut. like how high is a chinaman. asking for a tin of tartan paint or a left handed hammer. still worth a try eh.

Good one, as it is an electric train, there is no smoke billowing from the train.