W2 box 14 codes for Septa railroad employee return

There's two new codes in box 14 for the W2 for this return this year.

 

Septa regional rail worker.

 

RRMD?  Is there a correct code for that in the drop down?

WAGES -- same as box 1 wages?  Is there a box 14 code for WAGES?

 

What does TT do with these codes?  Or are the codes for IRS use?

What happens if you select code "other" or leave the code blank?

And why list WAGES in box 14?  It's already listed in box 1!