Quote:
Originally Posted by milomilo
So what are your definitions of rail transit?
Because at one end we have streetcars, and at the other we have the RER and Crossrail, with a massive spectrum of Metrolinks, C-Trains, Tubes, Skytrains and Subways in between each with unique characteristics. Do you really think there is a binary definition of LRT/rapid transit for all of them?
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I definitely agree that the types of transit are a spectrum and that in some systems there is overlap, but feel the vast majority fit comfortably within a category. There are about 175 existing metro systems and over 30 under construction, and I would be surprised if there is even a quarter of that number that cannot fit reasonably within a definition.
When I'm looking at an urban/suburban passenger rail system I consider anything that has all the traits of rapid transit to be a rapid transit or metro system, with some systems of course being more suburban/express oriented (like Washington metro) while others are more urban focused (Montreal metro).
Even if it's fully grade separated, if frequency is below 6 trains per hour per line for much of the day, I would classify it as commuter rail or light rail, depending on the rolling stock and alignment.
But these "middle grounds" are fairly rare since they don't usually make for a practical system. If you go through all the expense of fully grade separating the system, it doesn't make sense to not fully utilize the route by having high service frequency. And if you don't fully grade separate, then you can't have extremely high frequency due to safety and congestion concerns.
Systems like RER and Sydney Trains have a metro-like appearance in the city centre due to their high frequency from multiple lines being combined into a couple main corridors. But for most of their routes, they don't look anything like this and the outer branches cannot have metro-frequency due to the capacity of the inner city routes, and lack of full grade separation.