I also started that series when the 3rd book in the series had just reached paperback. If I recall correctly, they were on the air-tram thingy and had no idea if the landing spot was still operating. Big Blaine and Little Blaine is what I remember. A machine with an alter ego? I might have to pick it up again, but I've got The Shoes of Earhardt to read and 3 Cups of Tea while writing my own. Not enough time in the day.