Quote:
Originally Posted by fusili
But it is also a bus only road that can be converted easily to rail.
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Not if they design the transitways like the ones in Ottawa, they won't be.
The transitways were supposed to have been conceived as technology-neutral fully grade-separated transit rights-of-way. In some ways, they were supposed to be metro-like. But what happened in reality is that they became largely grade-separated busways. The distinction might seem minor, but it is telling too.
A busway is literally a bus-only road. It may or may not be fully grade separated (in that sense, it is the bus equivalent of a light rail line). As a bus-only road, it is designed like a road (in fact, a highway) by road engineers but with a few bus transit features, notably at stations.
A transitway, even one that starts out as a bus transitway, should still be designed in a way to facilitate conversion to some other form of transit, be it light rail or metro (indeed, the rough rail equivalent of a bus transitway is a light metro line, like Vancouver's Sky Train). But Ottawa's transitways were not truly designed as transitways - they were designed as grade separated busways.
The upshot is that conversion of the bus transitways to a rail transitway has not been thought through. For instance, when you convert, do you rip up the asphalt or lay ballast and tracks directly on top of the asphalt? With the latter, bridge clearances may become an issue where with the former they wouldn't be, but in the former any drainage lines could become an issue. Ottawa has both problems. Similarly, where do the supports for the overhead electrical supply go? It's much easier to design that in at the time of initial design and construction than decades later. Stations in particular are an issue for conversion due to issues like differing platform heights between bus and rail and the previous issue of build on top or rip up. Another issue with stations is that typical busway station designs are relatively short in length but are four lanes wide with another two lanes' worth of platforms either side, plus whatever elevators and stairwells may be needed, whereas rail stations are typically much longer but also narrower, and may even use a central platform. A true transitway built-out initially for buses would likely employ a staggered station design to keep it narrower that could be lengthened when converted to rail. Or it may even go so far as to consider contraflowing buses separated by a median with preplanned supports for future electrical - think light standards in the meantime - and median stations.
Be very careful with being sold on transitways that can supposedly be converted "easily". Unless Calgary makes sure that it doesn't just copy and paste Ottawa's bus transitways (and York Region's and Brisbane's amongst others), it will just be copying and pasting Ottawa's current problems a generation into the future.
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