Railroad ties are the long, wooden beams --often referred to as cross ties -- that are used to build railroad tracks. These same beams are often used to build retaining walls and to frame gardens in residential yards. Regardless of their use, railroad ties can rot and and splinter over time. If your ties get damaged, repair them rather than replacing them, as long as the damage isn't too substantial.
Examine each railroad tie on its own to see if it's damaged. If the railroad tie isn't damaged then there's no need to repair it and you can move on. If there are holes, rotting segments or splits in the railroad tie, remove it from the others for maintenance.
Determine the extent of the damage. If there are rotting sections in the railroad tie, figure out how big they are. If there are holes or splits, figure out how deep they run in that tie. If there's too much damage, such as more than one-third of the tie is going to have to go, consider just replacing it.
Repair the damage. If there is surface splintering on the tie, sand or grind it off. If there is rot, sand it away or saw it off. If there are holes in the tie, fill them with spike-hole filler compound, which is specifically meant to fill up holes in railroad ties.
Coat the railroad tie in a clear, protective compound. This is similar to painting your back deck, as the compound creates a barrier between the elements and the railroad tie. Use a coating that's meant to be used outdoors on wood. Alternatively, use environmentally safe paint that is designed to stand up to outdoor use.