>>1195909Sydney demolished theirs because it was a simpsons-tier meme monorail that was absolutely pointless.
A well planned monorail can be a good option, fitting between LRT and MRT. It offers almost as much capacity as MRT, but is a bit cheaper to build, but more expensive and intrusive than LRT. The main issue with monorails is that they're forcibly isolated systems, only make sense if they're elevated (if you build a tunnel then go for MRT right away), and switching systems are a hassle making switchbacks for easier operation complex and expensive, as well as junctions for branching lines.
Most of the times cities go with MRT instead because building elevated trains is out of fashion thanks to NIMBYs and the auto lobby pushing NIMBYism to make public transit more expensive. Otherwise if they want something cheaper they'll go with LRT. So there's little space to fit in Monorails. There's a bunch of modern and successful non-meme systems in Asia, where I guess NIMBYism isn't as big as in the west. Also classic applications for monorails are small lines serving specific needs, like transport within airports, theme parks, those kinds of things. There you can have an elevated structure, a small system that doesn't need lots of switches, and get high capacity for lower cost than a proper train.
