Joe,
Different size Lionel Tin Plate can confuse the beginning purchaser, the 600/2600 rolling stock is smaller in size than the 800/2800 series. The Cars are smaller, the Trucks are smaller, ect. Think of the 600/2600 series rolling stock as a PreWar 027, even though that is not what they really were. They were in fact a smaller less expensive Engine and Rolling Stock Consist, for those parents who could not afford the larger 800/2800 series Tin Plate Trains.
In reality in the early 1900's a nice 800 series Train with work consist or passenger Cars, with the beautiful Large Engine and Tender cost most men a full months pay to purchase.
This was one of the big reasons most little boys in my era got their Lionel Trains as Christmas Presents, it was a very big expensive gift.
In reality most middle class families settled for purchasing the 600/2600 series because they were less money.
Now here comes some more confusion for ya. Lionel also produced and sold mid size Tin Plate Engines and Tenders, the best example of this is the Gun Metal Gray 249, which looks correct with either 600 or 800 series rolling stock. This means you have Engines like the 259E as the normal 600/2600 series with 4 Wheel Tender, next comes the slightly bigger 249E mid size Engine and 4 wheel Tender that can pull either the 600 or 800 series rolling stock, and finally the big 263E or 260E Engine and 12 wheel Tenders that pulls the 800/2800 series rolling stock. All these different size Trains were in fact O Gauge Trains.
Further the very early Cast Engines and Tenders also were sold with Tin Plate Rolling Stock. Few of these were produced and they are very expensive today for sure.
If you would like to know more about a specific item there are a few guys like Bob and myself, PaPa Steve and others who own lots of different Tin Plate, and we will help you any way we can.
I hope this was not to confusing for ya. It is a little hard to follow if you have never been around Tin Plate. As George points out the rolling stock was built with more than a few variations. Remember also AF made lots of Tin Plate also.
PCRR/Dave
Tin Plate Trains the real little Boys Toys! The MTH P2 263E Work Train running on the over head shelf, FasTrack layout.