It's like this set is a smaller version of the 112 or 113 set. At least that's what the locomotive suggests.

Flat car

It's a good idea to be able to put some goods on the wagon (perhaps a log), but it would be nice if there were two pieces of tile under the log, so it would be easier to remove it from the wagon.

Mail car

Very nice. It's a shame that it doesn't have any inscriptions or logos, it's a bit average, but at least it can be built from any leftover blue bricks.

Locomotive

It's too simple, too childish for me. Much better could have been designed from this many parts. Something that has a little more texture and can be put together by a 4-5 year old. Or it would have been a good idea to build a smaller version of the characteristic locomotive of the 112 and 113 sets, so that they could also advertise the larger, motorized set.

Overall

I think it was a good idea to release a smaller entry-level set for the younger kids, but it would have required a nicer locomotive and maybe 1-2 more cars.

My Mod

Actually, I didn't like only the locomotive, so I built 2 versions of it. I built the locomotives on this 4x12 gray plate. Both are small tank engines or switch locomotives. One is a smaller scale version of the locomotive of the 112/113 set. Of course, I built it from parts that were available in 1966.

Both have a feed opening for the boiler.

And a simple passenger wagon and a Caboose would have been good for the set.