The luggage storage racks can accommodate quite a bit. The biggest factor is how much "stuff" others have placed there before you...however space comes and goes as people get on and off along the route. So if it's somewhat full when you board you may be able to move a bag down there later.

Depending on the actual size of your bags (from your description I'm picturing a typical airline rollaboard bag?) you may find decent space for some of them in the bedrooms...I've only looked inside a bedroom and haven't traveled in one (usually roomettes) so others will have more insight on bedroom space utility.

You'll have a great time on the train - enjoy!