Originally Posted by
Canadian Visitor
The word subway is generally used interchangeably with the word 'Metro' in much of the world.
Clearly, the word does originate in reference to tunnels, but many lines understood to be 'subways' including portions of the NYC system and the majority of Chicago's system, are in fact, above ground.
I wouldn't get too tied up in the terminology.
The goal, eventually, would be higher-order transit, on rails, that is entirely grade-separated [[does not share the road with other traffic and does not stop for traffic lights).
Whether one achieves this via an open trench, a tunnel, an elevated guideway, or some combination of these isn't overly important, though any choice will have trade-offs, including costs.
In general, tunneling is more expensive; however, going in a trench or above ground requires a great deal more property to be acquired. If that property can be found in an existing rail corridor, or highway corridor, and those make sense from a route perspective, then that may help save a lot of money.
However, if one has to buy up existing buildings and knock them down to build a new guideway, that can can be quite pricey.
Equally, when a guideway goes into a highway corridor, elevated or at highway grade, it doesn't tend to be seen as anymore of an eyesore than the highway itself; however, stations in the middle of highway overpasses are often not that appealing as walk-up locations for riders, who have to cross highway on/off ramps, and building bus terminals is complex and expensive [[decking over the highway).
An elevated Guideway beside homes can be seen as overbearing, casting large shadows, creating privacy issues, and the support columns can be graffiti magnets.
They can also be seen as psychological barriers between neighbourhoods, the same way as highways can.
That isn't an argument against going elevated by the way, just an illustration of the types of trade offs one must consider.
A big part of any plan needs to envision what you want the communities served by any new transit line to look like, once presumed gentrfication/redevelopment occurs.
How will the line induce and work with, what you want to see happen?
I suspect that the most likely scenario for Detriot would be a buried/tunneled line right in the downtown area, but one that climbs to either a trench or an elevated guideway once beyond the inner core.