The 31 units will be replaced with a 76-unit high-rise.
Ground Control was the first such game to replace individual units with "squads".
In these homes, units are replaced with a small set of rooms surrounding a common kitchen and living room.
All the units in the airline's fleet were replaced over the weekend, he said.
"We're replacing units that go back to the 20's and 30's, believe it or not."
To date, 628,000 units have been replaced or rewired, the company said.
No units have been replaced since the original construction.
In the late 1950s, the original electric multiple units built for the line were replaced by new Class 501 rolling stock.
No one could think of any objection, for the unit could be replaced in minutes, even if it did break down.
The 17-bed unit was replaced by a medical-surgical floor because of the hospital's need for more beds in that department.