I admit to being a gricer on the definition of one who likes to travel on unusual lines. Last year taking advantage of some diversions I managed to complete every line within the Birmingham city boundary. It is only recently that I have heard it meaning anyone exhibiting an interest in railways generally. I have never been a trainspotter or as I call them, a number taker, although in my youth, I spent many hours at weekends on both New Street and Snow Hill stations in Birmingham just watching the trains.
There is a thread on this forum entitled 'Micro Gricing at the Quail Level' but that in my opinion is taking things a little too far.
A few years ago, when spending sometime on the Harz, my travelling companion introduced me to a new term, 'Buffer Kisser' This is someone who when on a rail tour which might include sidings and other track not normally available to the general public will go right to the end of the train to show that they have travelled on as much of the track as possible. My friend who was in the front carriage on one such tour tells me there was a queue of people wanting to experience being at the front of the train.
I will also admit to being quite a bit of a gongoozler in my time. That is someone who stands and watches or walks along canals