FlightVideo

Reading on wiki. seems gear up landings happen to these guys also...
"In July 1983, C-5A Serial No. 68-0216 landed gear up at Travis Air Force Base, California. There were no injuries. The accident occurred while the crew was performing touch-and-go landings, and did not lower the landing gear during the final approach of the day. The aircraft received significant damage to the lower fuselage, ramp, clamshell doors, and main landing gear pods. The C-5A was later flown to Marietta for repairs. "

A 2x2 bogey would be pretty much impossible to steer and even trying would introduce severe sideforces on the strut unless the bogey itself was either articulated between the front and rear pairs or  both pairs could be independently steered like some 4 wheel steering cars..it would make the whole setup very complex
 

Interesting noseleg with the 4 wheels in line.  Anyone know why they did it that way instead of a 2x2 formation?

lancaster and B17 were about 65,000 ibs max take off weight
 
750,000 lbs ? (filled to the gunnels) - for the Galaxy ................ what a beast

The second picture has the person photoshopped in at a fake scale to make the gear look bigger, there is no aircraft with an undercarriage that size (also its not a C5 undercarriage anyway)
 
Here is a video showing work being done on the Gear...