Going above street level would require a bridge over the intersection for the LRT vehicles to travel on. The bridge is called an elevated guideway, and consists of a single deep beam that supports the weight of the bridge, LRT vehicles, snow, rain, wind, and so on.
The elevated guideway ramps up and down for about two blocks on each side of the intersection to get to its required height. It is typically supported on large concrete piers centered below the beam, but sometimes may need to be supported on a second layer of deep beams that span across the road onto concrete columns.
Due to the close proximity of the elevated station at West Edmonton Mall going underground is not considered feasible at 178 Street. Because an LRT stop can’t be placed on a slope, going above or below street level would usually mean that LRT stops intended to be placed near the intersection would need to be either shifted further from the intersection or built above street level as well.
Building above or below street level would be a departure from the City’s vision for a sustainable, urban, integrated, low-floor LRT system designed to blend into surrounding mature communities.
An elevated crossing would be more of a visual and potentially physical barrier. Building above or below street level would involve extending the tracks above ground from the elevated West Edmonton Mall station westward to cross over 178 Street and ramp down to ground level east of 182 Street. The 182 Street LRT stop is far enough away from 178 Street that it would probably be unaffected.