It's a case of 'where do you even start' really to be honest. I'd suggest looking at bringing in a consultant (or consultants) with experience in new businesses in the rail maintenance sector. Consider, premises, suitable directors and senior management, competent staff, competent safety management people, finance & accountancy, HR arrangements, insurance requirements, contracts experts and suchlike, and once all those questions have been answered then look at the things you'll need to box off to supply to rail organisations, this could be things like meeting environmental standards, having fatigue management systems in place or having staff trained to certain competencies etc. A lot will depend on what you want to do. If it's changing lightbulbs in railway stations for instance then that's a lot less specialised than if your company is going to be maintaining OHLE, but what you will find is many organisations on the railway will already have long-term contracts with people for these kinds of tasks. Will you be able to offer your services more competitively than the trusted suppliers who already hold agreements to supply this work?