This is NASA's giant crawler for its next generation spaceship. The crawler-transporter just passed "the first phase of an important milestone test."

According to NASA:
The Ground Systems Development and Operations Program completed testing of new traction roller bearings on crawler-transporter 2 (CT-2), on two of the massive vehicle's truck sections, A and C, in late January. The new roller bearing assemblies that were installed on one side of the crawler are visible in this Jan. 31, 2014 image. CT-2 returned to the Vehicle Assembly Building (VAB) at Kennedy Space Center, where work continues to install new roller bearing assemblies on the B and D truck sections.
These crawlers have been in use for 45 years. They've been upgraded "to increase the lifted-load capacity from 12 million to 18 million pounds to support the weight of the mobile launcher and future launch vehicles, including the SLS and Orion."