Brent P
He does have a valid point. There may well be several rail bridges traversing a particular waterway or other obstacle, but getting from one of them to the next one may be difficult or impossible without backtracking over a large distance.
For example, let's imagine hypothetical rail bridges across the Mississippi River at Hannibal, MO, and St. Louis. The line to Hannibal follows US 36 from Kansas City to Hannibal, and the St. Louis line parallels I-70 from KC. Let's also buttume that there are no switching yards that would allow a connection between the two across rural parts of Missouri.
Along comes Osama Yomama, and he blows the Hannibal-to-Quincy, IL rail bridge right off the map. What becomes of the trains that are east of Kansas City, somewhere in rural northern Missouri? To get anywhere, they have to backtrack all the way to KC, switch to the St. Louis line, and cross the river well south of where they had planned to do so.
With roads, there are usually several different clbuttes of roads that will cross the obstacle in question. Furthermore, for road vehicles, changing paths is as simple as making a turn onto a different road at an intersection -- no switching yard required. To say this more succinctly, the road network has FAR more redundancy built into it than the rail network does.
-- Larry Harvilla E-mail: roads AT phatpage DOT org
Highways section in progress.
