On Thu, Feb 6, 2020 at 05:57 AM, Donald B. Valentine wrote:

My late friend, and kitbasher extrodinaire, Robert W. Witbeck and I first began noticing that

many tank cars had dome platforms on only one side back in the mid-1990's but were never successful in determining

what factors decided whether on or two dome platforms were to be used

Don, it's era dependent. The ARA safety appliance drawing dated 1917, presented in the 1922 CBC, only shows one dome platform. I've always just assumed at some point the requirement was increased to one on each side, but never bothered to track down the date.

Dennis Storzek