For me, the tracking number didn't show up until the day it was delivered to my house. Not on the ELIS account, but on the Case Tracker, the status changed to:

"On October 27, 2016, the Post Office delivered your new card for Receipt Number XXXXXXXXXXXXX, to the address that you gave us. The tracking number assigned is XXXXXXXXXXXXXXXXXXXXXX. You can use your tracking number at www. USPS.com in the Quick Tools Tracking section."

That's why I thought it was weird that I would get a tracking number when it's already been delivered. For those who are waiting, I believe that once your status changes to "produced your card and mailed to your address" on ELIS or "approved your Form I-765" on the Case Tracker, you should get your EAD 3 days later. That's what happened to my brother and I.