In normal service braking (which is relevant to line capacity), the limiting factor is deceleration that is still comfortable for passengers, which is around 1.2-1.3 m/s². Both conventional high-speed trains and maglevs have brake systems that can sustain that deceleration for almost the entire braking process from initiation to stopping (and more in emergency braking), so all the difference comes from the higher top speed. Say if you compare 270 km/h (Tokaido Shinkansen line speed) and 500 km/h, braking distances should be lengthened to about 3.4 times.

I'm not sure what you mean by switches: maybe operation of a two-track line by using both tracks in both directions, that is sometimes diverting one train on the 'wrong' track? If yes, then I have two notes: on one hand, the higher acceleration of maglevs should mean that slowing down for track changes is less of a time loss; on the other hand, Japanese Shinkansen lines are operated in a strict one track one direction mode, so they may want to continue the same operational (and, as it wouldn't work without it, maintenance) practice.

_{*Lunatic*, n.
One whose delusions are out of fashion.}