While adding another WF beam is easy, it is not the most efficient way to reinforce crane runway beams. You should be concerned with the compression flange. Adding another beam will place the neutral axis lower from the top flange (compression flange) which will not buy you much top section properties.
I suggest adding two angles and weld them to the top flange. This way you can "lift" the neutral axes closer to the top flange while increasing its section modulus.
To compute the properties, as stated above, you need to go back to basics. If you can not do it by hand, you really have no business in attempting to reinforce a beam. The stress calculations are simple but rigorous. You have to have a good understanding of how to compute the allowable compressive strength. I doubt that the tensile stress will govern. You add area to the bottom flange very easily.
Another concern is the weld between the existing section and the new section to ensure composite action. That needs to be studies carefully.
If you do not know how to do this, it is OK to get expert help and expect to pay for it.
AISC has several article sin the Engineering Journal that addresses this topic. They also have a design guide that deals with industrial buildings which has a section on over head crane design. Gaylord and Gaylord have some write up and examples on crane runway and bridge design. Whiting crane handbook is one of the best texts written on overhead cranes. Unfortunately, it is out of print. I happen to have one copy in my library and I would not part with it for any price.
I have designed many cranes and written masters’ thesis on overhead crane and runway design. I could share some information with you if you need more help.
Regards,
Lutfi
