In AREMA 2011 Section 8.4 Unloading Pits, the General Note #10 in Figure 15-8-5 Unloading Pit - Four Foot max Span reads: "Horizontal equivalent fluid pressure on wall from backfill is 30 psf plus 11 feet of live load surcharge." This note is not repeated in Figure 15-8-6 Unloading Pit - Fifteen...