Of possible Interest:
The following article has information about the test as well as a mention that the unit will be on display in Old Sacramento on September 29, 30.
"ROSEVILLE, Calif., Aug. 22, 2012 /PRNewswire/ -- Union Pacific Railroad today unveiled an advanced experimental locomotive at its J.R. Davis Yard in Roseville that will test three emissions-reducing technologies including exhaust gas recirculation (EGR), diesel oxidation catalysts (DOC), and diesel particulate filters (DPF). Years in development, UP 9900 will be used for operations in northern California ranging approximately 200 miles from its base in Roseville. UP 9900 is the signature unit in a series of 25 locomotives that Union Pacific is analyzing as part of a broad test of various emissions-reduction techniques in northern and southern California. This is the latest step in the company's ongoing effort to design, build and test technologies that reduce emissions."
Press Release
This article has two photographs of the locomotive.
Sacramento Bee