Here is a picture that was published in the now defunct Rail Model Journal. The late Richard Hendrickson wrote the article that contained this picture. It shows where the AB brake system was installed. Rick Leach was kind enough to scan the article and extract the Shell photo.
Protocraft produced the decal set to support a Type-21 and also the Standard Tank Car 10,000 gallon car shown below. Now all we need is for Southern Car & Foundry to get moving on their STC kit.