covered hoppers

Can someone point out a web site that has a good guide to covered hoppers by various manufacturers, old and new? Just broad-brush stuff --
Cars by So-and-So look like this, cars by XYZ look like that, how to recognize the purpose based on the slope of the end sheets, that sort of thing ...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.