How do I make positioned sound on whole big object not point

Imagine noisy, large train passing by, from left to right. The train takes three lenghts of screen.

I'd like to create a positioned sound on whole of it, but seems like the sound is "placed" only at the imagepoint.

So when the imagepoint is off screen, sound fades but train is still on screen, yet silent. Is there any method for this?

Var Sound

Create Object INSound

Create Object OutSound

Screen

+----------------------+

+-----+ +-----+

| IN | |Out|

[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[]-[] ==> Movment Train

| | | |

+-----+ +-----+

+----------------------+

Train Is Overlap INSound - Volume Inc Volume Sound

Train Is Overlap OutSound - Volume Dec Volume Sound

At some point the training will be on IN and OUT but the volume will be balanced

When Train in "IN" Volume INC

When Train in "OU" Volume DEC

good luck!

Put the IN at the beginning of the screen and the more to the end

jcbarriento I get Your point, but situation is more complicated. Train is traveling across huge layout and the player will have the ability to get around it, above and below. Even if not seen, the train should be heard regardless of position in layout, but in proximity to player; hence the positioned sound.