A couple of points; firstly, contracts for new starters are required which include Sunday as a normal working day, this is basic common sense stuff. It matters not what the unions may or may not think about this, because no current staff members are going to take industrial action over colleagues who haven’t yet even joined the industry, so the DfT just need to get on with it and get it done. Get that in place and then at least you have some sort of solid bedrock for the future. The turnover within the guards grade can be pretty high, so it may well begin to have a positive impact sooner than some might think.
Secondly, it’s important to consider that staffing levels can play a part here as well, as the SWR disruption shows; it isn’t all about existing crew deciding they don’t want to work. Contracts are irrelevant if a certain TOC or depot has a lot of vacancies to fill, inevitably that means work is going uncovered. It also means that existing staff are likely to be working a higher degree of overtime all through the week to cover the outstanding work, which again means that Sundays are a less popular day for doing some extra.