I've had a folder on metra many times out of the bag during non-peak hours. The conductors never made me bungie it (but bring them just in case) and once even had me put it in a seat unbagged. They didn't have the handicap car open for some reason. Of course I'm sure the official line is, that if its not covered its a full size bike. Luckily you probably will still get on with a folder even if all the bike space is taken.