4 storage tracks at Ogilvie

Can someone please remind me of the name of the four storage tracks at Ogilvie? They are in the northeast corner of the station.

I think someone once said "mail tracks", or something like that.

Also, why is there a black tank car parked there frequently? Is it for fuel?

The four tracks in the northeast quadrant of UP's Chicago Passenger Terminal are indeed referred to as mail tracks, but tracks 1 and 3 are reserved for engine storage only. As you've correctly guessed, the black tank car is used for refueling, primarily on weekends...