I am using a flight diary website to log all my flights, but I am also looking for something similar to log my train rides. Also something for bus rides would be useful.
If you're in the UK, you can subscribe to Railmiles. It is primarily aimed at the UK as it will automatically fill in details like the operator, train ID, stock allocation (where available), booked and actual departure and arrival times, etc., using data from Realtime Trains. It does let you enter journeys for abroad though; there's nothing stopping you entering whatever you want. You can see my page here.
Conflict of interest statement: I am friends with the guy who runs this website, though I'm completely sure that I would be using the site even if I weren't friends with him :)