Why is it that when I use the corridor clipping tools and select a boundary only the components are removed and not the feature strings?
In the 3D view, the Linear Features are clipped by the program. Therefore, the model, the cross sections, the information that will be sent to native, etc... is correct and does not contain the clipped portion of the features.
In 2D, the features are not be clipped. The explanation here was that this is done so the features can be used as reference for other objects or other commands. In general, all the corridor graphics in 2D are for reference (such as the corridor boundary, superelevation lines, template drop handles etc...), and not really meant to be used for plan production.
Therefore, you should see this in the 3D Model:
But still see the linear features in the 2D Model, like this: