Circa 1917-18, The lithograph is the same as the previous series, except of course it's red in color. The major change here is the trucks. Whatever type you might call these trucks they were the first variation of the same type that IVES used right up until 1930, except these ones have plain sides with no embossing. These same red cars are also found with the somewhat later embossed trucks (see example below).

The example above is the red variation with the rivet detail, below the green variation. Both are probably early 1920s.

Green 60 with early 1920 trucks. The example below has less defined trucks from several years later.

Ives was never one to waste a part. Here they're using bodies already lithographed for a 550 series car on a frame that would probably date it to 1920-21,but it has 4 wheel trucks so technically it's a No. 60.

Another 550 on an 8-wheel frame, this one has the 1917 trucks with the smooth sides.

The example above is an 8-wheel 550 with a cutdown frame (1919?).

Circa 1922, just a color change. This variation comes in chocolate brown with an olive green roof.

Here's a hard one to explain, the frame and roof appear to be circa 1921-23, but the body is a 550 series body from approximately 1913. As was the case in 1913 only the baggage came in white, this car would have been sold with red 61 and 62 numbered cars. Some collectors claim this car is a fake made by other collectors, but original 550 series cars from 1913-14 would not have had any doors and would not have the slots punched into the sides for the door slide to attach to.  

Circa 1917-18. Red steel sided body with rivet detail and early smooth sided "M" style trucks (1917?). 

Circa 1918-19 - Still a mystery - IVES used some of the older 4 wheel frames and cut off the wings to make these extremely rare cut frame passenger cars. above is the green version. Several photos below is a red version with the cut frame.

Another 61 with a 551 body, I've included this one as you can see below that Ives made this car with two halfs that had a different color green.

Cut frame No 61 circa 1919.

Another example of Ives using bodies already numbered as 550 series cars on 60 series bodies. These cars would have been sold in sets listed with 60 series cars. Circa 1920. Below is the same car but just numbered 61.

Circa 1922. Chocolate brown body with olive green roof. Rivet detail, "M" style trucks that are embossed. Same car below but litho more maroon.

Circa 1924-25 later steel sided litho with 60 series number.

Circa 1917-18. Red with rivet detail, gray roof, smooth sided trucks. Example below from 1918-1919

Here is a 62 Parlor car on a cut down frame. These seem to appear between 1919 and 1922. These frames were taken from the 4 wheel 550 series cars and the pedistals were cut off to allow the 4 wheel trucks to swivel. We don't know if this was done to save money or they temporarily ran out of the regular frames. In any event these cars are rare.

Circa 1920-22. Leftover green 552 body on an 8 wheel frame, last series trucks with spring and rivet detail. 

Circa 1922. Chocolate brown body with rivet detail, green roof, last series trucks with spring and rivet detail. 

Ives didn't catalog a observation in this series until 1925 and then it was listed only as a No. 73. Here's an example of a No. 68 with steel litho and pre-1926 trucks.