I know it's already been mentioned, and is 6 (or 7) platforms, but Derby Midland deserves another plug. The 2019 remodelling made it a fascinating layout. Platforms 5/6/7 for the Midland Main Line, platforms 1&2 for the line to Birmingham, and a cute little crossover to allow platforms 3&4 to access both lines.
So the junction is both before AND after the station.
When a Voyager to Plymouth pulled in to platform 6 last week, straight away one can tell it's being diverted via Leicester. (Points failure at Stenson Junction)