Noticing that wooden bridges had a life-span of only about 10 years, he began looking at using iron for his bridges. At that time railroads made limited use of iron bridges. After a failure of an iron bridge on the New York and Erie in 1849, that railroad stopped using them.
He observed that wooden bridges had a lifespan of about 10 years, leading him to consider using iron for his bridges.  At the time, railroads were not commonly utilizing iron bridges. Following an iron bridge failure on the New York and Erie in 1849, this railroad stopped using iron bridges.