Speaking from a non-engineering and non-railway-insider angle, is there any way of futuro proofing to an extent, without increasing costs too much?
For example, leaving space between the platforms for four tracks instead of two? The two tracks would obviously need to run far enough apart to service both platforms and leave space in the centre for future tracks. This probably applies more to new builds. Surely, in this case, the only additional cost is more landscaping and a longer bridge?
Or building one of the two platforms as an Island platform, with hoarding to hide that fact? Therefore allowing two more tracks be laid the other side of the Island platform in the future? This probably applies more to adding stations to current trackwork.
Again, speaking from an outsider perspective.