TPF are files related to a software translator called Transit NXT. TPF files are used by the application to store a database of words or phrases. Each of these elements in the database is associated with other elements that constitute a translated version of the original into another language. The file is a translated version of the source file with the PPF extension.

The translated TPF file can be sent to the STAR group network servers - the creator of the Transit NXT tool. This allows you to update and extend the translation library used by the users of the program.