I suspect that, at least theoretically, the major impediment to the long distance Light Rail concept being proposed here, is the equipment itself. Some of the old interurbans that both Mr. Norman and I mentioned were probably some what "more" than today's Light Rail Systems
(particularly the North Shore Line, which, except for a small fleet of rather uncomfortable Cincinnati Car Co Curved Side Lightweight Cars, never gave in to the attraction during the depression of running light-weight equipment to save on power costs) using equipment which was much heavier than today's light rail vehicles. The Cincinnati & Lake Erie's "Red Devil" Cars, were both light weight and extremely fast, and were run over distances approaching 200 plus miles, yet, at high speeds were somewhat uncomfortable, having a tendancy for the rear ends to "whip" at high speeds. ( The P&W's Brill Bullet Cars, though vastly different in appearance, were almost identical electrically and mechanically to the "Devils", and riding on those cars which were run until 1990, would give one a good feel for what it was like to ride on a "Red Devil").
You probably could not sell the comfort level of most of today's LRV's as being anywhere near appropriate for long distance travel, though most of them are certainly adequate for urban transit use.
Please Move to the Rear and Speed Your Ride
( Philadelphia Transportation Company)