Randy Hees <hees@...>
There was historically a difference between the roof structure (carlines and purlines) and the sheeting (double board wood, Murphy, etc.) so until recently strong and rigid are functions of the structure, while rust resistant, leak-proof and cinder-proof (or fire proof? (We lit a wooden car on fire over labor day weekend at our museum from cinders from a wood burning steam loco)) are functions of the sheeting. Considering how long double board roofs survived in service I sometimes wonder about leak-proof.
No argument on cheap or weight (but railroads were not historically aggressive about reducing weight as one might expect. One significant argument for narrow gauge was the reduced weight.
I wonder about repair, forming, construction and transportation issues. Being railroad related industries, transportation wasnï¿½t really a problem, and most shops had the ability to lift large items. In an industry which was casting locomotive and tender frames in a single pour, and dealt with boiler plate on a daily basis roofs would not have challenged the technology.
I doubt that a typical shop tried to keep in stock replacement roof panels. More likely they would have either welded or riveted a patch, adapted the local common material, or ordered replacement material via the car owner if substantial repairs were needed. (or just scrapped the car and paid off the owner)