It can be found at Mount Blair trainyard, inside one of the train cars.
Despite the fact that the child in this holotape is singing that his name is James, and his father addresses him as James, the subtitles for this holotape name him as "Dan." In The 197 from DC, another holotape found at the trainyard, a man named Dan speaks to two other employees. Both him and the father in this holotape have the same voice actor, Larry Herron. Additionally, the child's editor ID for his voice type is "NPCM_MTR_MountBlair_James." This indicates that the "Dan" in this holotape was meant to be the father, and not the son.