Flight Crew Last 90 Days 156; Flight Crew Total 7976
Situational Awareness
ATC Issue All Types; Ground Incursion Taxiway
General None Reported / Taken
ATC Equipment / Nav Facility / Buildings; Airport
The taxiway centerline markings on ORD Taxiway K; K3 and A9 are worn off.  The line is almost gone in a number of locations.  At night using a 737 taxi light; it's very hard to see where you are going.  This area is away from the large bright lights of the terminal; and is a mass of darkness with a lot of blue lights.  It's even worse on a night when it is raining.
B737 First Officer reported the centerline markings on several taxiways at ORD Airport are worn and difficult to see at night.