Worth remembering that MSL's (and the law behind them) do not apply to just train drivers. The act covers Health services, Firefighters, teachers, border security and others.
Its a dangerous precedent to set just pulling the MSL's on the railway and then expecting other professions to have them imposed on them.
I am guessing this is just a stay of execution as far as rail workers are concerned, and that individual TOC's did not know what level of service to provide, let alone how they were going to provide it. It would not surprise me to find that "next time" the individual toc's (under a heap of pressure from the DFT) are more prepared to put a plan into action with the aim of running services on strike day.
I don't think that MSL's should be imposed on anyone, in any line of work. Industrial action is always a last resort. Is it any wonder public service workers are campaigning after 13-14 years of austerity?
I maintain what I posted earlier, better to avoid industrial disputes and resolve via dialogue.