Retaining wall

I need an “engineered design” for a railroad tie retaining wall. It will be about 3’6” tall. Should be very simple to design with vertical posts in front of the wall, deadman anchors, backfill with washed gravel and perf pipe at the bottom. The design committee in the subdivision I am building in will not allow me to build without the engineered design. I will attach a grading plan for reference.