Evolution of AAR loading gauges?? Standards for Plate B, Plate C, etc.

Have long wondered what the meaning of "plate" is, employed in clearance guidance.

A good broadside view of a 40-foot boxcar, new in 1939, showing the dimensional data:

EXW. 10-5     H. 13-1
E.W.     9-4    H. 14-0
I.L      40-6
I.W.      9-2
I.H.     10-0
CU.FT.3730

Inside Length-Width-Height are self-explanatory.

EXW is presumably the overall exterior width but what about E.W. 9-4 and the 13-1 / 14-0 heights?

This pic is an O-gauge model, presumably scale except for Lionel-type couplers and trucks with big-flange wheels. I'm supposing the dimensional data was based on an actual prototype car. This car appears 13 inches narrower overall than the 1939 example above.

 #27233 Lionel 2007

EAVES    ( HEIGHT 12 FT 10-1/4 IN
               ( WIDTH 9 FT 4 IN                                presumably the maximum overall width?
LENGTH (OUTSIDE 42 FT 1-1/2 IN
               (INSIDE 40 FT 6 IN

BUILT NEW 3-24

Ace posted:

EXW. 10-5     H. 13-1
E.W.     9-4    H. 14-0
I.L      40-6
I.W.      9-2
I.H.     10-0
CU.FT.3730

Inside Length-Width-Height are self-explanatory.

EXW is presumably the overall exterior width but what about E.W. 9-4 and the 13-1 / 14-0 heights?

 

E.W. is the width of car the at the sills, less ladders and grab irons.

13-1 refers to the height of the car at the sides and 14-0 at the height of the car at the top of the roofwalk.

Different car, same idea...

Rusty

Rusty Traque posted:

Ace posted:

EXW. 10-5     H. 13-1
E.W.     9-4    H. 14-0
I.L      40-6
I.W.      9-2
I.H.     10-0
CU.FT.3730

Inside Length-Width-Height are self-explanatory.

EXW is presumably the overall exterior width but what about E.W. 9-4 and the 13-1 / 14-0 heights? 

E.W. is the width of car the at the sills, less ladders and grab irons.

13-1 refers to the height of the car at the sides and 14-0 at the height of the car at the top of the roofwalk...

Rusty

Rusty, Thanks for the explanations. So the 9-4 and 13-1 specs seem pertinent to platform and roof clearances at loading facilities?

Here is another sample:

Funny, nothing about modern design hi-cubes, double stack, and autorack clearences....Clarence!