Quote:
Originally Posted by Nouvellecosse
Actually, they have a huge impact. Being electrified means that trains can accelerate much faster and therefore can run more frequently. It would be nearly impossible for a rapid transit system to function without electrification. And many true rapid transit systems are too busy to allow for things like fuel stops which would severely impact scheduling.
Being grade separated has equally high relevance, since many rapid transit systems run so frequently that if there were streets that cross the line at grade, the road vehicles would not get sufficient opportunity to cross as there would almost always be a train coming. This also means that the trains must be limited in their length to the length of the shortest block near a stop, since it cannot be allowed to block a crossing when it is stopped. Also, allowing outside access to the track reduces reliability since there's always the possibility of things like a vehicle stalling on the tracks, or a collision with a vehicle. As a result, LRT trains often need to be built differently with more robust collision standards in case of that possibility.
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But grade separation and power supply (and whether it is urban or not, for that matter) are redundant because they both are factors effecting frequency which is best considered on its own. If I have two transit systems that are identical in frequency and capacity, there is fundamentally no difference between them. Consider, for example, that the Sheppard Line has significantly lower frequency than the 201 in Calgary at peak periods (5-6 mins v. ~2-4 min, correct me if I'm wrong) despite the latter not being grade-separated. Both have high capacity and high frequency and are therefore best understood as serving the same function within their respective transportation systems.
Focusing on the grade separation is a meaningless distinction when it comes to understanding how the transportation system functions. It does impose limits on future capacity, but there are all sorts of implementation details that potentially have an even greater impact that you fail to consider in your criteria for rapid transit.
Finally, I don't think that there is any consensus at all amongst transportation professionals that rapid transit requires grade separation, at least the ones I know and have interacted with. The only source I can find is the APTA Glossary from 1994 that vaguely refers to segregated operations in its definition for rapid transit but that clearly acknowledges that actual terminology varies widely and that the function of the glossary is simply to get policy-makers up to speed. Most people I interact with acknowledge that there is a continuum from systems such as the Spadina LRT, which wouldn't really fit with most people's definition of rapid transit, to something like the C-Train which does, even though they are both technically light rail technology.
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