Circa 1918-1922 - Not much to distinquish this tank from others except the twist tab couplers and the shade of gray, o/w the date is pretty much a guess.  Note the one below is a different shade of gray.

Circa 1923-1928 -  We're dating this one solely on the orange paint which Ives didn't start using until approximately 1923. The one below is similar but came with a transitional freight set and has orange cradles.

Another Orange tank, this one is slighly different in that the sides are black and the whole top is black, not just the cap.

Here's a side view of the orange tank, count the rivets on each end and then compare it with the earlier version 

Circa 1929-1930 - Here's a hard one to find, Lionel body with Ives frame and brass plates. Out of the 122, 66 and 566, the above car is easily the rarest.