TRAXEdit is an HTML5-based editor for The Sims .hit files. It allows you to open and edit these files, and to visually add, modify, or delete TRAX records. Primarily used for adding grouped sounds to the game, it is a portable single HTML file that can be freely uploaded or embedded into any website.

Special thanks to peter9g.

For technical information on the .hit, .hot, and .hsm file formats in The Sims 1, along with three example ballon files:
TRAXEdit
http://www.simfileshare.net/download/5804495/
hit information
http://www.simfileshare.net/download/5804492/
hot hsm information
http://www.simfileshare.net/download/5804494/
sample
http://www.simfileshare.net/download/5804493/

Does this still work? (The site OR the docx files.) I get what appears to be an error message when I go to the site.

files has been moved to sim file share