Photo Credit: Alex Mead
This is a soldier pile and railroad tie retaining wall. These types of walls are common due to their relative ease of construction and the availability of materials. Simply place the vertical members, brown tubes in this case, and stack the railroad ties behind. Then, back fill can be placed behind the wall. One major problem with this wall, however, is the placing of the railroad ties. All joins should be staggered by many inches and secured with large spikes. As you can see on the far right this is not done, and greatly reduces the strength of the wall.