Help!! What are the circled pieces???

I can't for the life of me find these pieces in Stud.io! I want to use them for my own builds but I cannot find them no matter how hard I try, and I see them in other train builds and I'm wondering if anybody can help me out here. (Original MOC picture provided, built by The Lego Railway Series) submitted by /u/WDecently [link] [comments]