The DIY PVC Train Horn Guide comes as a PDF file and is downloadable after you make the payment. This guide comes with 68 high definition pictures and 36 pages, along with a very descriptive guide that goes step by step to show the process of how to make you very own train horns. One nice thing about these horns, is that they can be built in less than a day. These horns will cost around $20 to make from materials easily available at any local hardware store. This guide shows the process to make a 3" train horn, but the measurements can easily be scaled up to make a larger horn. The guide also shows how to tune your horns, so you can match the tones of other horns you like. To operate these horns you can use a portable air tank, they operate best a pressures ranging from 60-110 PSI. This would make a great summer project!!!