Stopping a Movie Clip without Controls

[Mental Image]

Hi,

I have a Flash project which has three scenes. In the third scene, I have a
train moving across the screen in about 400 frames. The train is stored in a
movie clip called "ChooChoo" (well, what else woudl I call it?!), and moves
from left to right with a - gotoAndStop("1") - action on the last frame to
return the animation to the beginning.

The movie clip is controlled by a keypress handler linked to a movie clip
stored off the stage, and the animation is triggered by pressing the "1"
key, thus:

on (keyPress "1") {
this.Scene3_ChooChoo.gotoAndPlay("2");
}

This is all fine, but what I would like to be able to do is to stop the
train animation no matter where it is in it's animation by pressing another
key, and then start it again when ready by pressing another key. I know that
this is probably basic stuff, but I have been out of the loop regarding
Flash for a while doing other things.

I am using Flash 8 Professional and Actionscript 2.0.

Thanks.