Seems like it would be difficult/impossible to get out at a high platform.
Also seems to me a bus to train transfer makes more sense. Why tie up a rail line with a bus that holds 15-20 people. Just drop them at a station and let them connect to a real train.
The old addage runs true: it's better to do one thing well than two things badly. It's neither a particularly effecient train not a particularly practical bus. It also looks hideous to the point of probably making children cry...
Another more successful application of the same basic idea is the tram-train. There are a number of them around the world, and the first city centre tracks have just been laid about two blocks from here in Strasbourg for a system that'll open in a few years time. Cities with tram trains include Karlsrühe, Saarbrücken, Paris, Lyon and arguably Sheffield, because the Sheffield Supertram is almost closer to an EMU than a tram in design.