[ssiguy]

The easiest way to define Metro is this...........................it can, hypothetically atleast, be automated.

Underground, elevated, at grade, capacity, technology are irrelevant as the lines have become so blurred but the ability to run autonated trains is what defines a Metro. This is why grade separated Toronto subway, Montreal Metro, Vancouver SkyTrain, Tokyo monorail, and Manillia LRT are all considered Metros. Edmonton, Calgary, and soon to be Ottawa all have LRT but not Metro like Manilla as they do not have 100% grade separation.

Everything else is either Light Rail {which can be operated from either end of the train, has doors on both sides of the train, and can have several trains coupled together}, streetcar {which is the same technology as LRT without the above enhancements}, commuter rail {diesel or electric, uses existing rail corridors but is not grade separated, and ussually is for peak hour commuting only} and BRT.

Does that satisfy everyone?