It's real! According to news reports and the Amtrak bike info page, the Empire Builder now accepts bikes checked trainside. What's especially awesome: Despite being unstaffed, the station at West Glacier nonetheless offers bike service! Glacier National Park, here we come!
Update 2016-07-06:
After talking to a friend who recently rode the Empire Builder with his bike and was skeptical about the prospects of walk-up service coming soon, I contacted Amtrak through their website. Here is their response:
Thank you for contacting us regarding walk-on bike service on long distance trains.In other words: Don't hold your breath...
[...] Currently, we have no information regarding projected dates in 2016 when walk-on bike service will be expanded on long distance trains, including the Empire Builder. Expansion of this service will be announced on our website, www.Amtrak.com at the News & Media link at the bottom of our homepage..
We hope this information will assist you.
Good news for cyclists in Wisconsin and Illinois! As the Bike Fed reports, starting May 4 Amtrak's Hiawatha line, which connects Milwaukee to Chicago, will start offering walk-up service for bikes. Previously your bike had to be partially disassembled and go into a box, whereas now you can just roll up your bike to the train and it will travel in the cab (after having made a 5-dollar reservation). This is not quite as good as the "walk on" service where you yourself roll the bike on and off the train, but it still is an improvement. Another, related limitation is that bikes can only travel between the respective downtown stations; all intermediate stops won't be served because the car in which the bikes travel will be locked.
For Madison residents the practical relevance of the new service is probably limited. If you want to go Chicago, instead of riding the 140 kilometers (85 miles) to the Multimodal Station in Milwaukee, you might as well bike approximately the same distance to Harvard, IL and take your bike on the Metra train. However, the ride to Milwaukee is arguably nicer (about 90 percent on trails), and Metra allows bikes only during off-peak hours. On the other hand, Metra is only $10.50 (no extra charge for bikes) versus $30 one way on Amtrak (including the $5 bike fee).
What is maybe more exciting for the Madison adventurous touring cyclist is that the Empire Builder will soon also offer walk up service for bikes. The Empire Builder travels between Chicago and Portland/Seattle, with attractive stops such as Glacier National Park in between. It's only about 50 kilometers (35 miles) to the Amtrak station in Columbus (Wisc.), and not having to deal with boxing up the bike makes a long-distance trip West seem much more attractive. There is no firm date yet for when this is going to happen, but hopefully it will still be this summer.
Next step: Get walk-on service on the train to Madison. Oh, wait...