passenger and freight car design

Can anyone suggest a source of information on identifying the size and style of passenger and freight cars used in different eras? I/m trying to model in the 1900-1925 steam era, and need to know what type, size, and shape rolling stock is appropriate. Thanks.

Actully, for freight cars the quickist way would probally be to review the Westerfield(sp) website. They also sell Copies of
offical guides which are helpfull.
For Passenger cars you want to stick with the “heavy weights” offered by Riverossi and IHC.

If you live near a BIG city library, see if it has a “Railway Car Builders Cyclopedia” for 1925. There are many, many, websites out there, most railroad specific. Try “Railroad Freight Cars” and “Railroad Passenger Cars” on Google. Heck, I found photos of a railroad that quit in 1936 through Google!