func osmRelationToTrainLine(osm *osm.Osm, index *osm.Index, relation osm.Relation) (trainLine model.TrainLine) { var sections model.Sections for _, member := range relation.WayMembers() { way := index.WayById(member.Ref) if way != nil { sections = append(sections, wayToSection(osm, index, *way)) } } trainLine.Sections = sections return trainLine }