Circa 1910-1912 - The lithograph changed in 1910, the frame didn't. Note that these are the earliest 2nd series one gauge passenger cars. They have the high sides with the "New York Central Lines" visible at the top. They have single point truss rods and the one above has hook couplers (1910-1911) and the white one below has automatic couplers (1912).

Circa 1910-11 - White high side (with New York Central Letterboard) baggage car.

Circa 1913-15 - White low-sided (no letterboard) baggage car.

Circa 1910-13 - The car above is the earliest version with the high letter boards, single point truss rods and hook couplers. The car below still has the high letter boards but has two point embossed truss rods with automatic couplers (probably 1913). IVES first cut off the top of the car in 1912 when they used these bodies on 0 gauge trucks, but contrary to popular belief, these high letter board cars do appear after 1912. 

The cars above and below are from 1910-11 with hook couplers, high letterboards and double support truss rods.

Circa 1913-1916 - 2nd series litho with low sides. Below is the same car in the brown litho

Circa 1917-1920 - 3rd series lithograph - reverts back to high letter boards.

Circa 1912-1913 - The Chicago car above has high letter boards, single point truss rods and automatic couplers. The car below, besides being white is also different in that it has two point embossed truss rods. 

The car above is circa 1910-11 with high letterboards, hook couplers and single support truss rods. Note the differences in the car below which is probably from 1912.

End view of a No. 72 Chicago car, circa 1914.

Circa 1913-1916 - Low side white Chicago car, note that the car below is identical except IVES made it into an observation.

These observation cars that show up using the older Chicago body are scarce, probably circa 1916-1917 and may have been made just to provide an observation car for people that had one of the older 1 gauge sets. See back below.

Circa 1913-1916 - Low side Chicago car, below is the same car that has been made into an observation. Although you can't see it in this picture, IVES lithographed some of these trucks with spring detail, we believe this was done when the cars were included with sets headed by either a late No. 40 or early No. 1129. These Steam Locomotives had tenders that had the later style trucks. 

Circa 1917-1920 - 3rd series cars Washington above and Observation below