On beta-6 I can only get on a train when standing on a platform block. That makes sense but I have lots of platforms built on deserts, forests, etc. and the row of blocks one block from the train which should be platform blocks were replaced by other blocks to match the environment. So now I can't walk onto a train on those platforms. Could you please add an option to let us decide whether players should be on a platform block to enter a train?

You can now place platform blocks on ground level and cover them up with one block.

for me, i use stone as floor or use carpets to cover the platform blocks
you can just put psd/apgs, also the use of platform block is for train doors to open

Oh, you're right but I forgot to mention that those platform blocks were hidden one block below the platform to ensure train doors are open. A cross-section may look like this:
S S S W . R . S S
S S S P S S S S S
where W is for wool, P is for platform block, and R is for rail.
Yes the train door opens in this way and that may be a bug but it does help to make the platform more customized.
Covering with carpets is a great solution in some cases. But humps on both sides of the platform still look odd. And I don't want screen doors on platforms built in the wild for some reason.
Okay, I may be demanding here so these are just my ideas on this feature.

for me, i use stone as floor or use carpets to cover the platform blocks
you can just put psd/apgs, also the use of platform block is for train doors to open