>>974641The rolling stocks isn't that much cheaper, but then again, it isn't that much more expensive either (mind you narrow gauge has pretty large network itself).
Narrow gauge is cheaper in a sense that it could negotiate tighter curve, thus it can be built at more challenging topography than standard gauge. Narrow gauge tracks also has axle load as high as 25 ton axle, so it can be used to haul cargo just as well.
Really, the only apparent drawback of narrow gauge is speed (100 mile/hour vs 200+mile hour for standard gauge tracks).
