Picture a giant honeycomb cell, made of composite materials, and stacks of them to make a community.
Dimensions inside 12 foot long, 8 feet high, 8 feet wide. Heat and noise insulated. Nylon rails on exterior, which fit into matching steel rails of the main honeycomb structure. This allows for for easy removal and insertion from a stack, if a unit gets trashed or contaminated in any way. Unit is set up to make it easy to move around with a forklift.
One one end, a door system, sliding to left, right, and up, so as to not obstruct or hit anyone standing outside, This end contains all the connections for power, communications, heat and air conditioning, and small plumbing stuff, for vanity sink.
On the other end, a window, with appropriate shade systems. Small washbasin inside. Bed(s), table, and large screen computer/tv.
Restrooms, showers, kitchens are common to clusters of these units, clusters segregated by sexual preference (as many as are called for for a given locality), and by single/married. Avriation can be made for larger family units
The modular design allows for stacking, and for the removal of individual units without disturbing the rest, for cleaning and repair.
Transporting these would be 3 to a semi trailer, and vertically on a flat car, about 8 of them on a standard 89 foot flatcar.
A shorter version of these could be made for emergency use on rail cars, which are limited to loads no wider than 10.5. They could be interlocked stacked two high, and these would be used for emergency shelter in disaster areas, like Hurricane Katrina. In this configuration, you could get 15 to a flatcar, and a mile long train could quickly carry over 5,000 housing units anywhere above high water. Multiple trains could be used to evacuate large numbers of people, to points well away. People animals and stuff, into compartments, lock doors, and away you go.
This is a real shelter solution, all we need is the political will to implement it.
Wifi throughout area, and kitchen/laundry/bath could each have a semi trailer of their own. Set up in a "U" shaped corral, and pprotected by water proof roof, a commons with tables and play areas.