Denny Anspach <danspach@...>
About 20 years ago, I was a guest on a motorcar inspection trip over the southern remaining trackage of the former interurban Fort Dodge, Des Moines & Southern RR, newly re-minted as the tourist Boone & Scenic Valley RR. The principal features of the railroad were two substantial bridges in the beautiful Des Moines River valley: a high spindly trestle over a deep side-ravine (we would call it a canyon here), and a more substantial and longer bridge over the Des Moines River itself (the famed massive C&NW Kate Shelley high bridge over the Des Moines was- and still is ,of course- not too many miles downstream. We stopped to "inspect" each of these impressive FDDM&S bridges, and I commented in what great shape they seemed to be, much of the steel still having its mill finish intact (pretty important maintenance issue for a tourist line!). It was explained to me then that the bridges' great shape was due to the fact that the railroad historically hauled very few reefers "...to drip brine to corrode the steel,- unlike the Kate Shelley bridge which is currently so heavily corroded from refrigerator brine that they are constantly repairing it" .
I note that the Kate Shelley bridge is apparently currently slated for replacement. It would be interesting to know to what extent this giant project has resulted from years of brine corrosion (probably mostly from PFE cars :-) ).
Denny S. Anspach, MD