I have heard of the Royal Slope Railroad in Washington state, but do not know if it has ever gone into active service. It goes from Royal City to a connection in Othello with the Columbia Basin Railroad.
Last I knew it was out of service and has been for many years.
WRL/ Washington Royal Line (Frontier Rail/ Paul Didelius) … In service with a hopelessly oversized SD45 (ex MRL 331) plus the Alco MRS-1 rusted to the rail
Maybe they should use something smaller like some GP50s, MP15AC or Gensets.