my first scratch-builds

My first scratch built flat car came from ehre:  http://www.pcrnmra.org/sierra/shortline.htmlusing the plans in the 2011 4th quarter issue.  Starting simple has its benefits...

The flat on the right, just in front of the caboose, is scratch built, as are the loads on both.  The article I mentioned is where the plans came from.

Of course, that came after my first scratch built locomotive, a dummy class A 2' gauge climax.  It came out nice, although I wish I had made it a little bit narrower.  Lesson learned:  Each one built makes the next one a little bit better...

Car Builder's Cyclopedia

 Search for Car Builder's Dictionary or Car Builder's Cyclopedia.  Both were names of books published by real railroads that had plans for cars and their components in them.  Older ones are often on line on Google Books (and by older that means 1800's early 1900''s).

Other opportunities are to look for an old Carstens publication on car plans, "Traction Plan Book" or "Rolling Stock Plan Book" .  Kalmbach did the same type of thing but I can't find its title off hand.

Find a index of model railroad magazines and look for plans for rolling stock in the index, then look for those issues.  If they are recent enough, they may be available as back issues.  Otherwise buy some "Mainline Modeler" magazines, they always had plans in them.

I've built many tank cars

 I've built many tank cars over the years. I was given plans for three cars that came from Dupont, plans from magazines, even plans from a old wooden kit. The photo is of the car I built using one set of the Dupont plans. The photo is by outstanding modeler, Tony Sessions and used with his permission.

Back issues

They don't do it so much anymore, but back in the day, the major model railroad magazines routinely published drawings (usually in HO scale, or 1/2 HO scale) of all sorts of rolling stock. Check back issues of MR, RMC, NG&SLG, etc.

Another way is to simply google the car type you are interested in followed by the words "drawings" or "plans" (100 ton covered hopper plans).

They don't have dimensions,

They don't have dimensions, and I don't know how accurate they are, but-

http://trainiax.net/me55-rs.php

Beautiful model Bobby Pitts,

Beautiful model Bobby Pitts, I suspect that is a rather unusual car.

Diagrams

If you are into modeling the modern era, have at the BNSF Customers site. There you’ll find diagrams and dimensions of almost all types of cars they are running.

http://www.bnsf.com/customers/how-can-i-ship/individual-railcar/#%23subtabs-3

Kurt

Good job

Nice work!

Joe