Thanks to a thread started by brianel about a sale at Lionel Direct of the Lionel Dinosaur Set, I purchased one of the sets. That set has become a favorite of a 2 year old, and, a 5 year old that visit the layout.
I bought some plastic easter eggs that are hinged, and open [Amazon] to replace the eggs that come with the set, are solid plastic, and don't open. I also bought some miniature dinosaurs [Amazon] as "hatchlings" to put into the eggs. Both boys have a great time loading and unloading the eggs onto the gondola that comes with the set, and, the two additional Lionel gondolas that I have added to the set.
Their mom holds the 2 year old in her lap while he gleefully runs the set with the LionChief remote.