Railroad ties are a popular way to create outdoor steps and add natural wood to your landscaping. They are cheap, readily found and very durable. However, railroad ties are usually treated with creosote, a chemical poisonous to humans, and so cannot be used where food may be grown. They are also very heavy and will require two people to lay. Consider this when planning your steps and also determine how many steps are required. If more than three, you will need to anchor the steps in the ground to reinforce the walkway.
Survey your yard and decide on the placement of your steps. Measure the desired width of the steps. If the railroad ties are not the same length or not the correct length, you will need to cut them with the chainsaw to the desired length.
Dig a trench about 3 inches deep where your first tie will be placed. Place a layer of stone, making sure it is level, and then lay your first tie in position.
You will need to anchor your railroad tie in the ground if you are going to construct more than three steps. Drill a hole about a foot from either end of the tie, all the way through the tie and into the ground. Hammer a piece of rebar into the hole until it is flush with the top of the railroad tie.
Measure two feet back from the first railroad tie and mark where you will place the second. Level the ground between them and then lay your second tie as you did the first, digging a trench, laying a level of stone, and then anchoring the tie with the rebar.
Fill in the space between the ties with gravel (or the material of your choice). Repeat for additional steps.