Oct 21, 2014 - 12:55 PM
Hello garyol, and welcome to MySwissAlps.com!
If you plan to use public transportation only for Zurich-Lucerne-Engelberg v.v., you can best buy regular train tickets for the adults and Junior Cards for the children. However, if you do make any other trip by train, bus or cable car, a Swiss Half Fare Card combined with the free STS Family Card could be more economical. For example, if you and your family plan to visit the Titlis, the Swiss Half Fare Card option turns out cheaper than buying regular tickets. So you'll have to make sure what your exact plans are and make calculations based upon your itinerary.
I hope this helps you decide!