The Dreamlifter is a stock Boeing 747-400 that has been modified to handle larger volume freight (not necessarily heavier but oversize) for Boeing's 787 assembly program. Only 3 of these planes exist, with one more to be converted. They are used solely for transporting sections of the 787 between the factories in Italy, Japan, Charleston, Wichita and final assembly in Everett, Washington. The entire tail assembly swings open on the hinges seen in the photo.
This 747 was originally delivered to China Airlines in 1990 and was put in storage in 2005. Boeing purchased it in 2006 and did the conversion by 2007.