When you walk into the museum, you walk into a massive display of planning and executing the railroads across California and the West transformed America. Again, this picture DOES NOT do this justice. If you want to learn something, read through as much as you can at the exhibit and try not to gawk at the amazing engine that is part of it.
As an aside, I've been wanting to go this museum for the last several years. It's multiple levels of real trains is mind boggling and the Sefton Collection just caps it.