If you can tell that your bell has unreadable writing on it, you might try taking a rubbing. Rubbing is a simple procedure of placing a piece of thin paper over the object, taping it in place so the paper doesn’t shift while rubbing, and rubbing over the writing with a soft pencil or crayon until the information has been transferred to the paper and, hopefully, is more readable. No guarantees, of course, because the results will vary depending on the condition of the object. There are several videos on http://www.youtube.com that demonstrate how to make a gravestone rubbing. The method is the same.
Since you have a PRR railroad bell, you may want to go to the website: railroadiana.org and ask if they can help you.