Hello All:

I need some help with understanding European wheel sets. My understanding is that all modern MARKLIN GAUGE 1 will come equipped with NEM wheels.
I know NOTHING about RP25 but I'm told it exists. I understand FINE SCALE as having lower profile flanges. And I just recently heard the term 1 PUR as an option on the FINE MODELS website. Can anyone shed light on these four designations?

If I were to use MARKLIN GAUGE 1 track - could I run either of these four wheel sets or would I have problems of some sort - for example general tracking or going through switches? Is there a track that is more universal (KM1) that would run all of them? As GAUGE 1 takes up considerable space - I'd like to make sure my wheel sets and my track play well together. Not a lot of additional space for several tracks to function with multiple wheel sets.

Thank you all in advance!

John