Re: RAILROAD BRIDGES

Most R.R. Truss bridges that were built in the early 20th century were over-built, they had to make allowances for the recipocating motion of the engines, they just made them with a whole lotta mass, look at the huge truss bridges that cross the Ohio river that were built in the teens, they have had no retrofitting, they were overbuilt at the time, the truss bridges that were built for car/truck use, were sized for the weight of the cars/trucks at that time, they had no idea that trucks weighing 80,000 lbs., or more, would be crossing them 40-50-60-70-80 years later