Mass and Capacity - any information around

I have been looking into the bin files of some of the rolling stock. I see some of them them have a cargo compartment section and some don't have any info there. The cargo compartment appears to be for rolling stock that you can load and unload. I recently downloaded some new boxcars by Michael Stephan and he said he tried to improve the physics but really didnt go into what he did. So I took a look at his files and see that he aded a cargo compartment to his boxcar's bin files.
I end up with two variables. Mass and Capacity. But there is no clue as to what these really are. So I conclude that MASS is the weight of an empty car. The value for the default boxcar is 27.3960. My question is, is that tons? Or is the decimal point really a comma and it means 27 thousand and 396 pounds? Or is it some other system's weight configuration. How much would a real empty boxcar weigh? 27 tons or 27,000 pounds/13.5tons?
In his cargo compartment Michael added the value of 60.7900 to the CAPACITY of it. Is this the new total weight of the car and load or just the weight of the cargo? Is it tons or pounds or?
I am also assuming if you select the car in a scenario and load it, it will be heavier to pull?
Has anyone attempted at doing any of this before. I do not find much with a search results on several forums.
I end up with two variables. Mass and Capacity. But there is no clue as to what these really are. So I conclude that MASS is the weight of an empty car. The value for the default boxcar is 27.3960. My question is, is that tons? Or is the decimal point really a comma and it means 27 thousand and 396 pounds? Or is it some other system's weight configuration. How much would a real empty boxcar weigh? 27 tons or 27,000 pounds/13.5tons?
In his cargo compartment Michael added the value of 60.7900 to the CAPACITY of it. Is this the new total weight of the car and load or just the weight of the cargo? Is it tons or pounds or?
I am also assuming if you select the car in a scenario and load it, it will be heavier to pull?
Has anyone attempted at doing any of this before. I do not find much with a search results on several forums.