Interrailler or Interrailer, which one is correct?

Question

Which one is true to express people who make Interrail travel?

One "l" or double "ll".

Also some of pages are typing as InterRaillers, interraillers. Should I start with upper case for both Interrail and Interraillers in the sentence?

Example:

Interraillers love travelling the Europe's hidden places.

Answer 1

-ail + -er = -ailer, with just one L; hence jailer, mailer, trailer, etc. So, it would be Interrailers.