Please make a backup of your file (better safe than sorry)!

This variation of the script in overly_large_max_files_or_scenes_that_take_up_a_lot_of_memory gets rid of all the animation layers (the assumption being that you don't want them anymore):

t=trackviewnodes;n=t[#Anim_Layer_Control_Manager];deleteTrackViewController t n.controller;gc()

Note that this is just one line (depending on you setup the blog may display it over more than one line).

Maybe you've got a file where both the original post and this one don't help, you can make get rid of other top level nodes in trackview. As this is potentially much more dangerous i'm not going to present this as a complete script. 

First of all we need to get a list of the available trackviewnodes:

showproperties trackviewnodes
.Video_Post : TrackViewNode
.Global_Tracks : TrackViewNode
.Biped : TrackViewNode
.Anim_Layer_Control_Manager : Controller
.BatchRenderManager : TrackViewNode
.SceneStateManager : TrackViewNode
. : TrackViewNode


In the line of MAXScript replace Anim_Layer_Control_Manager with one of the trackviewnodes: Video_Post, Global_Tracks, Biped etc.

If there isn't anything in the trackviewnode you'll get an error: -- Unknown property: "controller" in undefined

And depending on what's in the scene you may get more nodes than are listed above.