Replace Title with filename - Newbie queston

I recently purchased an MP3 player and I'm sure it will be fine once I've figured out a couple of things. The main one that is driving me nuts is that it picks up the meta data and uses the 'Title' to list the songs.

Most of what I have does not have meta data. So the filenames were all 'Track 01' and on and on. Add several discs of this stuff, and the mp3 player lists 14 'Track 01' songs when trying to create a play list. Not useful.

So I took the time to go through every single mp3 and re-name it. I thought this would work. I did not know about meta data, and the problem remains.

So now I am trying to use Mp3tag to change the title information. I created the following action:

Field: Title
Original: %_TITLE%
Replace With:%_FILENAME%

And nothing happens.

What am I doing wrong?

I've very carefully picked all the filenames, and if I could just get that data into the title I'm sure things would be better.

Thank you.

Action type: Format value
Field: TITLE
Format string: %_filename%

Thank you!!!