This has been discussed a bit in another related thread, but I now realise that it belongs in its own one. Unidirectional streecars like those in Toronto and Philladelphia, and in Pittsburgh (before being converted into LRT, mostly with high platforms), require all stops being located on the right hand side, which is the kerbside of all two-way streets in North America. Among legacy systems, even New Orleans seems to have platforms/access only on the right, judging from photos and footage I've seen. Was this generally the case with first generation systems in North America, whether uni or bidirectional running was used? Yet newer systems, even the essentially street based Portland streetcar has platforms on both sides. In light of the practice on legacy systems, one wonders whether island platforms make sense in the street enivroment. First of all, stops on many four lane roads are necessarily on the kerb side. Given that most newer systems have platforms on both sides, is equipment provided to make sure that doors are opened on the platform side, and if not, have there been any cases of drivers opening the wrong doors?
Furthermore center island platforms require slewing of rails and overhead wires, and in fact, slewing tracks around offset side island platforms actually takes up less lateral space that do center island platforms, the latter also requires greater slewing of tracks.
If a stop is located in a cutting or on an embankment, or if there is an elevated or underground walkway where the stop is located island platforms allow for sharing vertical access between both sides, rather than being duplicated or available on only one side. But on a street based system, stops of that sort are exceptions, and, for all we know, they could be in locations where it is easy to arrange for one direction to passover the other, and thus could run on the left where island platforms are useful, thus making island platforms possible where needed, even with doors on only the right.
Furthermore center island platforms require slewing of rails and overhead wires, and in fact, slewing tracks around offset side island platforms actually takes up less lateral space that do center island platforms, the latter also requires greater slewing of tracks.
If a stop is located in a cutting or on an embankment, or if there is an elevated or underground walkway where the stop is located island platforms allow for sharing vertical access between both sides, rather than being duplicated or available on only one side. But on a street based system, stops of that sort are exceptions, and, for all we know, they could be in locations where it is easy to arrange for one direction to passover the other, and thus could run on the left where island platforms are useful, thus making island platforms possible where needed, even with doors on only the right.
Also known as Myrtonos