Gardening and railroad ties
There are many opinions about using railroad ties around garden beds used for food production. Some University horticulture departments approve the use of old railroad ties for gardening and building raised beds. However, creosote used to preserve the ties is known to be carcinogenic and harmful to humans. In fact this is what the US Environmental Protection Agency says about use of wood preserved with creosote.
Creosote is derived from the distillation of tar from wood or coal. Pesticide products containing creosote as the active ingredient are used to protect wood against termites, fungi, mites and other pests that can degrade or threaten the integrity of wood products. It is used in outdoor settings such as in railroad ties and utility poles.
Certified pesticide applicators in wood-preserving facilities use specialized high pressure equipment to apply creosote to wood.
Creosote is not approved to treat wood for residential use, including landscaping timbers, garden borders, or wood that may come into contact with food (e.g., cutting boards, countertops) or drinking water.
Homeowners should not encounter creosote-treated wood in the residential environment. If they do, it can be disposed of by ordinary trash collection (i.e., as municipal solid waste). Check with your local waste management agency.
Creosote-treated wood cannot be reused in other products such as mulch.
Do not burn creosote-treated wood because serious health problems can occur from breathing smoke or vapors.
The soil around the railroad ties on your property have more than likely leached creosote into the soil. I suggest that you find another area to plant the blueberries.