If a small-scale clean coal fueled power plant is co-fueled with 5% of creosote-treated used-up sleeper wood, the decontamination by carbonisation at 500 °C in an indirectly heated rotary kiln with the diameter 1.7 m and effective length 10 m can be realized. It should be included in the "3R Clean Coal Carbonisation Plant" system, which processes coal. It will improve the heat balance of the system, since the carbonisation of wood will deliver a lot of high caloricity pyroligneous vapour to the joint furnace of the "3R Clean Coal Carbonisation Plant". Pine wood sleeper sapwood contains 0.25% of sulphur, but the average pine sleeper wood (sapwood and heartwood) 0.05% of sulphur. Most of the sulphur is lost with the pyroligneous vapour and burned in the furnace. Since the "3R Clean Coal Carbonisation Plant" is equipped with a flue gases cleaning system, the SO2 emission level will not exceed 5 mg/m3. The charcoal of the sapwood portion of sleepers and that of the average sleeper wood will contain 0.22% and 0.035% of sulphur, respectively. The increase of the carbonisation temperature does not substantially decrease the sulphur content in charcoal, although it is sufficiently low, and the charcoal can be co-fired with clean coal. The considered process is suitable for small power plants, if the biomass input in the common energy balance is 5 to 10%. If the mean distance of sleepers transportation for Central and Eastern Europe is estimated not to exceed 200 km, the co-combustion of clean coal and carbonized sleepers would be an acceptable option from the environmental and economic points of view.