Both solutions would take months/years to implement.
"More trains" mean they need to radically improve service/repairs and/or purchase of new trains.
"Expand the station" would mean that they would have to shut down all-of or large-parts of it while works take place. I remember being impacted of the London Bridge train station de-spaghetti-fying the tracks. I moved out of the area I was living so eventually I was impacted for only 4-5 months.
London bridge tracks untangled is so much better for throughput - I remember so many long waits as a Brighton train blocked the whole station crossing the tracks.
One surprising good thing the gov did at that time was insist on the rebuild of the station itself, it was particularly grim, and just a mess.
I've lived nearby the whole time and the new station is a nice space, generally efficient with good throughput for the trains.
I'm pessimistic, but really hoping they don't stick with plans to build a too small terminus in London for HS1, not too optimistic as we have Rachael Reeves as a continuity austerity Chancellor - lets see.
"More trains" mean they need to radically improve service/repairs and/or purchase of new trains.
"Expand the station" would mean that they would have to shut down all-of or large-parts of it while works take place. I remember being impacted of the London Bridge train station de-spaghetti-fying the tracks. I moved out of the area I was living so eventually I was impacted for only 4-5 months.
I will not touch the matter of costs.