It sounds like a weird idea at first, but maybe it could actually work. Kind-of like running two trains on top of each other instead of after each other. I guess the downside would be the need for bespoke rolling stock and larger platforms. I think, it would generally be preferable to double the frequency or run longer trains. But it could be interesting if you’ve already exhausted those.
Two level platform? Then you’re actually boarding double the number of passengers, could be useful in very busy stations.
It sounds like a weird idea at first, but maybe it could actually work. Kind-of like running two trains on top of each other instead of after each other. I guess the downside would be the need for bespoke rolling stock and larger platforms. I think, it would generally be preferable to double the frequency or run longer trains. But it could be interesting if you’ve already exhausted those.