How can you tell DMUs aren't made for running in the city?
(I'm making a full post about this because I'm tired of having to dig up the links from comments; this is primarily for background for future postings).
Pictures from Camden, NJ, on the RiverLine, which is also inappropriately labelled "light rail" by the same people trying to mislead you about our starter line here in Austin:
Doesn't look so bad. Just a bit of a corner, right? Keep going.
Further down the street to the south (down in the first image):
Try it yourself - click on any one of those images and then drag to navigate along the supposed "light" railway - and see how they managed to get it into the city core.
Any questions? This isn't light rail - it's a freight rail line bulldozed through a bunch of city blocks; which we don't have the latitude to do here in Austin, since our downtown blocks actually have some economic value.