B747 Captain reported a main landing gear failure on the right hand body gear on taxi after landing. The aircraft stopped on the taxiway and was raised up to free the strut and was towed to the gate.

Narrative

On the ILS XR at ZZZ; upon selecting flaps 25; we had a brief 'GEAR DISAGREE' caution. It went away; flap and gear indications were normal; and we proceeded to land at flap setting 25. The FO's landing was gentle; we exited the runway on taxiway D; crossed Runway XL and turned left onto taxiway K. Coming out of the turn we felt a slight bump as if we had rolled through a pothole. Within seconds we had 'GEAR DISAGREE' and 'CONFIG GEAR' messages. We decided to stop the taxi and requested tower to send a vehicle for an outside inspection. The driver reported visible damage to our landing gear. I called our local operations and they sent maintenance for a more detailed evaluation. We were told our right main/body gear had collapsed/tilted up into its doors. Over the next four hours we were surrounded by maintenance and rescue vehicles; attempts were made to elevate the aircraft and to release the right main/body gear.After that was accomplished (Cockpit indications went back to a normal 'gear down' at this point!) we were towed to the ramp. Halfway through this process; the tug failed; had to be pulled away by a second tug; and a third tug was attached to the aircraft to continue the tow. We were offered to vacate the aircraft early in the process; but the crew decided to stay with the aircraft; not knowing how long it would take. Only after parking and exiting the aircraft; were we able to see the damage to the aircraft ourselves. CRM worked well on board; all four pilots were involved; put thought and effort into the operation. Maintenance and chief pilot on the ground regularly and thoroughly briefed us through the intercom on events outside the aircraft. Never was a question of fault implied in the communication. Mechanical failure of component of the landing gear caused the right main/body gear to collapse and tilt upwards into its own closed bay doors.