No, no comments on the track number in the title.
Now, to get that absolutely clear: are we talking about the tag-field TITLE or the filename?
If you want to manipulate the TITLE it would be best to have also a filled TRACK field. If that is not yet filled (can be checked in the files list of MP3tag) use the numbering wizard to get an ascending sequence.
And here comes the bit for TITLE:
Create a new action (see FAQs for that: /t/967/1 with a name of your choice, e.g. "Number titles"
Select the type "Format value"
Select the field TITLE.
Enter as format string:
$num(%track%,2)_%title%
Press OK and OK again and Close.
Select the files that should get the modified TITLE and then select the action from the Dropdown list Actions.
Run this action only once per file as you otherwise will get duplicate track numbers in front.