The first time it is run, it creates the training database, and will continue to use that database everytime you run training mode until you delete the SambaTrain.sdf file which is located with your SambaSettings.txt file.
Or, you can change the Training.vbs script (first line of code, change to TRUE) to create a new training database everytime you run training mode. To change the script, you may need to give yourself permission to modify the file thru Properties -> Security as by default you only have Read & Execute permission.
Also, you can tell that your in training mode because at the bottom left of the login screen it will show SAMBA POS 2.xx - CE, instead of SAMBA POS 2.xx - SQ
CE - Compact SQL
SQ - SQL Express
When you exit training mode, you return to the normal version of SambaPOS.