According to TMZ, The video was apparently shot over the weekend during a steam-engine train ride from Durango to Silverton, cutting through the San Juan National Forest. 😳 As they were chugging along, it seems a group of passengers noticed what they believed to be a bigfoot walking along on the side of a mountain they were passing, and they caught him. A rep for the USDA Forest Service -- which has jurisdiction over the San Juan National Forest -- tells TMZ ... they're well aware of this new video "evidence" recorded last weekend, but they're not prepared to weigh in on its validity. [🎥: @tmz_tv ]