It doesn't HAVE to be an autotile. And frankly it probably shouldn't be either, since there's no way to turn off an autotile and the escalators in FrLg only moved when the player stepped onto them.
You should use a Character Sheet, like how the door events work. If an animation has more than 4 frames, use the Change Graphic command instead of the Turn commands. If it has more than 16 frames, separate the animation out into multiple character sheets.
^This is how it looks in my game.
Here are the character sheets I've got set up for these:
Please feel free to use these (anyone). It's not like I own them, they're game rips after all.
EDIT: It's a very tiny detail, but I'd recommend setting Move Animation to off for the player after the first move action where they step onto the escalator. That way they don't keep walking as they get moved upwards. Just remember to turn it back on again once they reach the top.