Golden Pass Train valid on Bernese Oberland pass

Myself, my wife and my 1 year kid are planning to stay in Lauterbrunnen for 5 days. So we find Bernese Oberland regional pass more suitable. We are also interested in travel on Golden Pass train.
As per the validity range for Bernese Oberland pass, on free days, travel between Gstaad and Brienz is free. However, does this validity also holds true to travel on Golden Pass Train? So, if I have Bernese oberland pass, on free days, I can also use Golden pass train for free (and at 50% on other days)?

Thanks very much, that helps me to make the decision. Our 1 year kid is also travelling with us. Even if his travel with us is free of charge, is there a family card or any other card I should purchase / request for him? If yes, how to make such request? I have been through the information but I am not very clear on the concept of Family card.

Hi surawap. You don't need any ticket or pass for your 1-year old child.