I can see that having people
paid different amounts, or receiving different numbers of holiday days, or different benefits, is terrible for morale.
But I can't see why simply employing people to work on days on which the existing workforce demonstrably do not wish to commit to working (otherwise the problem would not exist) would be in any way an issue. Wasn't that the solution for the Night Tube in the end, to employ drivers specifically for it? OK, it wouldn't be viable to employ Sunday-only drivers, but it would presumably be viable to employ drivers (other traincrew are of course available and required
) who worked Sundays plus N other days each week.
It's not really different conditions in a wider sense, it's just like some businesses, rather than a rota, employ people who always work mornings or always work nights.
If that is felt to be the case, then withdraw the Sunday services entirely. It is not acceptable to advertise them and then not actually operate them reliably due to the inability of TOCs to organise / staff to accept a contractual setup to ensure their proper delivery.
It is
not acceptable to advertise a service knowing full well you barely have any chance of delivering it. That option should not even be on the table; it should be considered a serious breach of franchise with heavy financial penalties which would make it worth the TOCs' while to solve the issue properly. (That is, it should cost the TOC
substantially more than they save by not operating the service or by putting buses on instead).