I'll believe it when they start jackhammering the existing platform. I suspect there may be some confusion because the FRA enacted some
new ADA compliance rules that went into effect early this year. Projects which began on or after February 1, 2012 would need to meet the new rules, but projects begun before that date would not (at least not yet -- all Amtrak stations except flag stops need to be fully handicapped accessible, whatever that means,
by September 2015).
The new Northstar station in Ramsey needs to comply with the new rules, but the Union Depot probably skirts by, at least for now. Actually, the Ramsey station falls into an exception class since it's right along mainline tracks. Current Northstar stations appear to be compliant because they have mini-high platforms and the trains are equipped with onboard lifts (I've never seen the lifts used, so I don't know how well they work). The Union Depot would probably need to comply with stricter rules since their tracks are technically off the mainline and shouldn't carry freight trains (though I wouldn't be surprised if someone tries to sneak something through there).
There may also be confusion because Amtrak Superliners have 18" floors while the Wisconsin Talgos are apparently 21 or 22 inches above the rails. This whole ADA compliance issue got brought up last year as the Wisconsin legislature blocked further payments to Talgo, even though I don't think they would have really been affected by the new rules.
I'm not sure how high the Northstar's BiLevels are. It sounds like stations with dedicated tracks serving trains with multiple different equipment types are supposed to build platforms at the height of the lowest floor among them, but it's hard to say what to do in the Twin Cities when there are multiple different heights being used and there may be more waiting in the wings. (Incidentally, I think the Hiawatha Line trains have 14" floors.)
Here's one graphic (
found here) showing different floor and platform heights (and it clearly doesn't show everything out there):
Train Platform Heights.jpg
Trying to have everything be roll-on/roll-off across the country just isn't going to happen without a massive investment (billions, I would guess). Some stations can have multiple platforms with different heights, but there's still a variety of equipment out there which isn't very consistent. Not to mention that there are corporate and governmental rules and regulations out there worrying about equipment (or
workers) hanging off the sides. These rules seem pretty antiquated, but it's hard to get the railroads and other interested parties to change their minds about clearance issues. In fact, I'd be willing to bet that the FRA themselves are inconsistent about platform heights and clearance (though they seem to be more realistic about it now than they were a few years ago).