Building a Rail Buggy:

 If your dead set on building a Rail Buggy from scratch, there's three routes you can take. The first and easiest is to buy an existing frame from one of the manufacturers or vendors. They've already done the engineering and head-scratching to know that the design is sound. I would personally have the chassis made with DOM tubing and not the more typical welded steel. You may also have a choice of suspension systems. Talk with the manufacturer about that and let him guide you on what works best for your driving and budget.

The second route you can take is to order a set of plans and build one from the tubing up. You will need certain specialty tools such as a welder, tubing notcher, chop saw, and grinder. You can use a metal blade in a circular saw to replace the chop saw. It's not easy but it can be done. Also you can use a grinder to fish-mouth the tubing where it meets or better yet Harbor Freight sells an inexpensive notcher. (not the best quality in the world, but it works)  A tubing bender is a nice tool to have but these are expensive ($400 and up).  Check your local muffler shop to see if they will bend your tubing as per your specs.

Also, go to the bookstore and order the book called "Metal Fabricators Handbook" it will be well worth the money.

The third route is to bend your own creation. This is not something I would recommend to a beginner. There's just too many things that you could miss.