Wagon Blueprints & decal tutorial

Hi! Is there anyone who knows where to find blueprints/reference pictures of simple wagons (like the one´s the cowboys used to have, ore more simple)?
And are there any tutorials out there on the subject of how to do decals in Blender?
I know I’ve seen one, but I can´t remember the adress.

decal tutorial:

http://www.ingiebee.com/tutorials/Decal%20Mirror%20Modelling/theeth%20decal.htm

Thanx! That´s exactly the one I was looking for!