This was a great learning experience. Same as the GitHub example, but now with Leaflet.
[iframe src="http://gisforthought.com/projects/trans_siberian/trans_sib_insert.html" width="100%" height="550"]
In addition we have the following in the header:
So the route is being read directly from a .geojson file. Although it has been renamed to route.js, and "var route = [" has been added to the beginning of the file and "]" to the end.