It was often hard to tell these features apart from up in the air. There are many instances of pilots losing races because they followed the wrong rail line.

It was often hard to tell these features apart from up in the air. There are many instances of pilots losing races because they followed the wrong rail line. For a really in-depth history of pre-electronic navigation, check out "Most Probable Position" by Wright, http://www.amazon.com/Most-Probable-Position-History-Navigation/dp/0700600922 http://www.amazon.com/Most-Probable-Position-History-Navigat...