The Merry Prankster
Pactum serva
So important that 70% of the worlds railways can do without it and suffer no problems whatsoever. Yep, that'll be the one. Anyway Southern have just had a huge recruitment drive to appoint hundreds of new On Board Supervisors. Doing the job of the guard for cheaper. Makes good business sense to me. So you're not having your jobs automated, you are being gotten rid of for a cheaper option.
This is a meaningless statement. Maybe 70% of railways are suitable for DOO and 30% aren't.