Passengers in the observation lounge car were invited to send letters using stationery decorated with this colorful letterhead.
Click to download a PDF showing the entire first page of this four-page stationery. (The other three pages are blank.)
In addition to the postcard shown in a previous post, the railroad also happily gave out other postcards advertising its train.
This one shows the Empire Builder between Seattle and Everett along the Puget Sound.
In this one, the train is further east, probably along the Columbia River in Washington state.