Afraid your post falls down with the first sentence...simply trains and buses are different. So it may work on a bus but that certainly doesn't mean it'll work on a train.
In the example you for it would be a stronger argument to suggest that the cost effective way of operating a Sunday service there is to run a bus instead of a train though...
Oh my ! Cancel Magnet, apply brake, Stop at station, apply DRA, brake at Step 3, Desk to neutral, get out of seat, find T Key, pick up ticket machine, Open cab door, shut cab door, You forgot your coat, and it's slashing down, so go back for coat, shut cab door again, Do all guard's duties opening doors, one door only mind you so all punters are running down platform with babies bouncing in buggies to get to you, stand in door, selling tickets 1 by 1 as the punters get on, after they have stood there in the rain, oh hang on, you want a single to London via Ipswich, hold on, I'll just bring that one up, that's £5,678.97 p HOW MUCH !! etc., etc., etc. Train is now 12 minutes late
Do all guards duties shutting doors, open cab door, shut cab door, put ticket machine and T key away, take off soaking wet coat and hang it up, put controller to forward, put brake to step one, check DOO platform equipment, remove DRA, take power, release brake
" Ptschhhooooooooooooooooooooooo !!!!!!!!!!! " Flash, flash, flash, flash.....................
FUC, BALLOX, ****E, with all that going on I forgot that the FIRST thing I did in this huge and lengthy farrago was CANCEL THE MAGNET, I forgot the signal on the end of the platform was RED and I've had a SASSPAD and am out of a job !!
Driver's drive and don't give a toss about tickets
Guard's guard and sell tickets
Other people worry about just about tickets
Get real !