It is a 10 x 4 !/4 straight flange I-beam 30' span
John's question is valid, without the thickness of the steel in the flanges as well as the web, there is no way to answer that question. What also needs to be known is the strength of the cables as well as the capacity of the trolley itself? You need to give more detail in your question. You also need to state whether or not there is any kind of safety factor built in, or is the weight to be at maximum component capability, or design capability. There is a very wide difference between the 2 conditions. If you don't mind doing your own work, you might want to get a copy of Machinery's Handbook, 27/th edition, or later from Industrial Press. If not, and you are a college student, then you might consider a different major.
I Built a House and used a 26 Ft Metal beam in my Garage (w/living space above), By Engineering Design, it had to be 14” Wide. Metal Beams are rated Depending the TYPE of Steel they are Made of, and the Design of the Beam itself (I-Beams come in either S-Type or W-Type). So Any Answer someone gives you may Not be Correct for the Beam you end up buying. The steel supply you get the beams from usually will calculate the loads and sizes for you at no charge. Any Wooden Beam including A Glue-Lamb would have to be so thick that you would Not have enough room to walk under. A 30’ long Metal Beam is Going to be Back-Breaking Work to position and install… Good Luck!
Thickness of steel? Quality of steel?