Awesome Train Whistle with PVC – How to make Today I will show you how to make a simple train whistle with multiple tones using some PVC. This design consists of 3 individual whistles combined to make the familiar train whistle sound. To make this project, you will need some 1/2-inch PVC pipe & fittings, a 5/8-inch wooden dowel, a saw, a hammer, a ruler, and a metal file or sand paper. I first cut the PVC into 4, 6, and 8 inch pipes. These lengths are important because they help determine the tone of each pipe. It is possible to tune each whistle to a specific musical key by adjusting the lengths further, but I wanted to keep it simple, so I chose 4, 6, and 8. Next cut a notch about 1-inch from one end of the first pipe. The angle of the notch is important to help make the sound. The first cut needs to be at a 90 degree angle. The second cut needs to be at 45 degrees. Both cuts need to intersect about half way through the pipe. Now take the wooden dowel and place it next to the pipe on the notch side. Cut a piece just shorter than the small section of the pipe. Then using a file, flatten one side of the wood, removing around 1/8 of the diameter. Next the dowel needs to be hammered into the PVC. MAKE SURE THE FLATTENED SIDE IS FACING OUT TOWARDS THE NOTCH. The dowel needs to be inserted until the front edge is level with the 90 degree cut of the notch. Then repeat these steps for the other two pipes. The rest of the assembly is pretty simple. Placing an end cap on the long side of the PVC should complete each whistle. Test each one to make sure it works and make adjustments if needed. Using some additional pipe and fittings, I combined all three pipes together to make the train whistle sound. The sizes and lengths of these additional pieces are not critical, so customized them as you wish. Now you can have fun with your new whistles!