If you like those stamps you should check the USPS philatelic web site. Just got the latest catalog from them and they have a set of pins with the three stamps on them and a "boxed set" of a book on the history of building the railroads, the trains and the story behind the stamps. Also includes a sheet of stamps and six color proof printings of the colors used to print the stamps. About $80 for the package.
And the stamps are still available for order from the philatelic service even though they sold out long ago at local post offices.