Drawings of the side view and top view of switchbacks with retaining walls entitled 'Switchback With Rock Retaining Wall'.

The top image of the side view of a switchback:

• Arrows and text are used to show the 'Insloped tread' and 'Outsloped tread'.
  
  
• Arrows point to the two stacks of rocks which make up the retaining wall. These are labeled 'Retaining wall'.
  
  
• The original slop of the ground before the retaining walls were put in is shown with a dotted line and labeled 'Original ground line'.
  
  
• A ditch carved in the hill on the uphill side to the retaining walls is labeled 'Drain ditch'.
  
  
• The slope of the retaining walls is labeled with a triangle at a 2:1 slope and is labeled 'Batter 2:1'.

The bottom image of the top view of a switchback:

• The two retaining walls on the downhill sides are shown with arrows and are labeled 'Retaining wall'.
  
  
• The 'Inslope' and 'Outslope' are labeled and showin with a set of three arrows, each getting shorter as they get closer to the landing.
  
  
• The upgrade is shown with an arrow and labeled 'Upgrade'.
  
  
• The landing is where the switchback starts in a new direction and is labeled 'Landing (0- to 5-percent outslope)'.
  
  
• The ditch on the uphill side of the trail is marked with an arrow and labeled 'Drain ditch'.
  
  
• On the uphill side of the trail the 'Cut slope' is labeled, and on the downhill side of the trail the 'Fill slope' is labeled.