How many axles will it take

That's flat out crazy. I've seen overhead cranes from .5 tons to 300 tons. Most overhead cranes you will encounter will lift nowhere near 150 tons. That's like saying "most trailers can haul 150-250 tons".

 

I'll tell you what we run into all the time is something will weigh 75,000 lbs and they will say 75 tons, or vice versa.

You also run into the metric ton/ US ton confusion from time to time. Metric ton will usually have the abbreviation MT.

 

I see them routinely in the steel mill.

Here is one from China

http://image.made-in-china.com/43f34j00neftKCSFPAzw/250-Ton-Overhead-Crane-with-Hook-QD250-50-.jpg

 

He is not hauling anything and has not in over a decade. But he has done it all.

 

The Manitowoc MLC 300 counterweights are marked 10 tons but say 22,000 pounds.