A beautiful old beast.
But the costs are beyond massive.
When built, airconditioning was just invented.
Typewriters were human powered.
All the building services will have to be substantially increased for current and future needs.
Where do you place them? Fire protection, how do you install a sprinkler in a herringbone ceiling? At what cost?
Many engineers and architects with sharp pencils can overcome huge problems.
Half a million sq ft (usable?) 200 sq ft per person?
WHERE WILL THEY PARK THEIR CARS?
Parking can equal floor space.
They need a TEN ACRE PARKING LOT OR LARGER!
And access roads, fire lanes...
Detroit, home of the car.
That's the easy part. Plenty of room for a parking structure on and over the old platform areas behind the station. There's probably some baggage space under the station that could be re-purposed, as well. Then there's the park in front of it which might be available for underground parking.
In Fort Worth they converted the old office floors to loft apartments and they still have enough parking available for the park and ride for the rail service to DFW Airport and downtown Dallas.