Click tren... Give credit if you want horn and/or train.
I made the sound with my mouth, cloned it twice, and changed speed. So there's 3 pitches at once to make it cooler. It also has a L-Bell (also my voice but sped up). I watched way too many train videos as a kid. It stands for Liam12LenoxSouthern because I was 12 when I made this.