The idea is you can have smaller “everything” and just run trains closer together from the start to make up for it. VAL does this the most elegantly, with 60-second headways. It’s pure magic to watch. This was also the key design ideology behind ICTS (Scarborough RT*, Vancouver SkyTrain) - run small trains as fast and as close together as you can.
* - This never quite happened in Scarborough for a myriad of reasons, most notably the failure of the vehicles to successfully navigate a previously-built superstructure with too tight of a radius, necessitating a total rethink of the functional design of a terminus station meaning train lengths had to be doubled and headways halved - but that’s another story!
* - This never quite happened in Scarborough for a myriad of reasons, most notably the failure of the vehicles to successfully navigate a previously-built superstructure with too tight of a radius, necessitating a total rethink of the functional design of a terminus station meaning train lengths had to be doubled and headways halved - but that’s another story!