Strange enough, I didn't dive into the motor. Just a quick response test. I tried a different approach and cleaned the cars and shells. This gave me a second look at what I had and some time to take note on what was broken. My cleaning is a soft brush and liquid had soap. I had some mysterious black marks and rust spots on the inside of some shells. I used a little Goo Gone and green scotch Brite to remove them.
Now the grey flatcar, I took pictures of all the broken areas lon all the other cars. The flat car is clean and sure enough that was the question. I will get a picture, I mention this as a set and I use the term loosely from the 64, 65 era. That is because I have two engine numbers. The dummy is 213 from 1964 and the engine is 216 from 1965, both of the same Minnie and ST Lou.
Some repair required here.
The grey flatcar is the same time period in the Doyle book, it is listed as unnumbered but was made from a 1877 cast. Interesting enough these cars had military items by Payton Plastics and were green in color. That is the mytery of this car. No value was given but having an original load is needed for value.
In the final inspection, the grey car is stamped 1877-3 on the backside near one end under the coupler. Now the original 1877 car is a coraal car with a fence that had some horses and came in a General Set from 1959 and 1960. It was black too. This is also from the Doyles Reference.