Gather iron ingots
Gather sticks
Open a crafting table
Place 1 stick in the center of the crafting grid
Place 2 iron ingots in the left and right of the center stick
Place 3 iron ingots in the left column
Place 3 iron ingots in the right column
Leave the top and bottom middle slots empty
Take the 16 rails from the crafting result
Place rails on the ground to build the railroad