I read the article on "Are railroad ties safe gardening." I have a slightly different question. I need to build a retaining wall on the slope in my backyard to prevent further soil erosion. No humans will play or access the backyard (it is a steep slope) except for future maintenance. Are railroad ties safe for this application or do you recommend an alternative? I need for the wood to go into the ground about 3 to 4 feet and above ground about the same. Thank you for your consideration.
Here is more information on the use of railroad ties and their safety.