I've always understood that: A wagon is the part of a train that is used for transporting goods, produce, food and products (collectively known as freight). A coach is where people sit (also known as a carriage).

waggon-Any of various kinds of wheeled vehicles drawn by an animal or a tractor coach-A railcar where passengers ride.waggon-goods train coach-passenger train (terms used ) whats the difference between goods train and passenger train ?