Measure the area to determine how many railroad ties are need. Railroad ties are usually 8 or 9 feet in length.
Contact local the local rail yard and ask for a list of building contractors they use. Railroad ties are replaced as a regular part of railroad maintenance. However, it is illegal to take railroad ties when they are piled along the track. Building contractors have contracts with rail yards to legally remove and sell used railroad ties. The rail yard can supply you with the name of the contractors in your area responsible for railroad tie removals.
Visit major home supply stores, which sell railroad ties for landscaping.
Search the Internet for railroad ties suppliers in your area. Magicyellow.com provides a list of railroad tie suppliers for each state. It is also possible to find railroad salvage companies online that sell railroad ties in bulk for a low price. If your landscaping project is elaborate and requires a large number of railroad ties, this is the most inexpensive option.