...run Amtrak's Great Dome on the route between Washington and Chicago in peak seasons and market the feature. This was done to what I perceived as a great deal of success on the Adirondack last fall, and the marketing was only minimal, but the project received a substantial amount of coverage in the press. Amtrak owns only one Great Dome, and it's normally kept out west for special excursions, but the Cardinal, since it's a single level train (and consequently has no sight seeing car) that travels through very picturesque scenery, is an ideal candidate for the Great Dome. And since the Cardinal runs only three times a week, getting the dome onto the majority of the runs is viable. The expense is limited to maintenance on the Dome (which is in good condition) and the minimal cost of bringing it to Chicago from California. The only other thing I'd do to the Cardinal is add on an extra sleeper car in peak periods. The train runs with just one viewliner right now, and as a result, sleeper prices are just absurdly high. If there was more availability of sleeper rooms at reasonable prices, it would actually be my preferred train to get to Chicago on business when I had the time to kill.
If we were to consider "big ticket" ideas for the Cardinal and Amtrak's Long Distance network in general, I believe this is a way to bring the Cardinal back up in terms of ridership and possibly a daily run. Here's the concept:
The Cardinal currently runs from New York to Washington to Cincinnati to Indianapolis to Chicago. Heading west, the train could split (like the Empire Builder) in Cincy or Indianapolis with one section continuing to Chicago as usual, and the other section continuing to Effingham or Centralia (for City of New Orleans connections), St. Louis (for Texas Eagle/Sunset Limited connections), and possibly Kansas City (for Southwest Chief connections). Heading east, both sections combine again in either Cincy or Indianapolis, of course. This of course means a new route, but not necessarily new stations. If you think about it, much of the Cardinal's problems with ridership today stem from three main problems: on time performance, with missed connections in Chicago, lack of "big cities" at reasonable hours, and the slow speed. Couple those shortcomings with the fact that the Capital Limited and Lake Shore are much faster trains, and the Cardinal carries very few people making east-west trips if they're not getting on/off in the Virginias.
In that sense, if Amtrak was to have a single long distance train that served the Northeast Corridor from NY-Washington, served Virginia, provided a one-seat ride to Missouri cities, AND provided a direct, RELIABLE, EASY connection to New Orleans, Texas, and California, it would represent a service that would not only alleviate crowding on the Capital and Lake Shore, but it would also help with crowding and confusion at Chicago. And the biproduct of that added service, obviously, is a new breath of fresh air for the oft-forgotten Cardinal.