Search parameter limitations

As info:

  In Global Skills Finder BI I did a search for "rail operating rules qualified" the search produced zero qualified employees.  I know the skills are pulled from WorkDay and this is not provided as skills that anyone can select.  If I was looking for employees with experience in rail operating rules, how would I find them?  Maybe we allow some freeform skills to be written in Workday so that they can be pulled into Global Skills finder.