Directors on the right track for In Fog And Falling Snow at National Railway Museum

"The ambition of the staging is preposterous!" said actor George Costigan, who will play the disgraced Railway King George Hudson in Mike Kenny and Bridget Foreman's play about the formative days of York's railway history from tomorrow.

"What the directors [Damian Cruden, Juliet Forster and Katie Posner] and the writers imagined they could do is so audacious, but the confidence comes from having done The Railway Children at the NRM, the York Mystery Plays and Blood + Chocolate. From courage comes achievement."

Sitting with Damian, Juliet and Katie over lunch in the Station Hall at the National Railway Museum, you can sense how they are meeting their audacious challenge head on.

The Station Hall will be one of three locations for the York Theatre Royal, Pilot Theatre and National Railway Museum co-production, as will the Great Hall and the purpose-built, 1,000-seat Signal Box theatre.

"I can't wait; I'm really excited, genuinely," says Katie, Pilot Theatre's associate director. "Especially now that we're in tech week. You get the feeling of something really special about to happen."

"There's been a different rhythm to working on this show at the NRM than when we did The Railway Children," says Damian, the Theatre Royal's artistic director. "The rehearsal process has been much longer. We started doing skills workshops in mid-March and then began the rehearsals in April. It's been more like when we did the Mystery Plays in the Museum Gardens or Two Planks And A Passion at the Theatre Royal."

Like Katie, Theatre Royal associate director Juliet Forster is raring to go. "It gets to the stage where you just want it to start because you carry it with you for so long," she says. "It's the size of the cast that excites me. 200 people! That's rare. This is the largest cast I've worked with, as I wasn't involved in the Mystery Plays.

"There's a huge age range, from seven to cast members in their 80s, and there's a huge difference in the people on stage. They reflect us, they reflect York; they're not professional actors; they're have their own voice."

The play starts with a question, says Damian. "It's not answered but it's a journey of discovery," he says, explaining how the pioneering railway network entrepreneur George Hudson is put under the spotlight on the path to becoming "York's dirty secret".

The first half takes the form of a series of vignettes, divided between the Great Hall and the Station Hall, which can be seen in any order to build up a profile of Hudson and those who blossomed or were scorched by his influence on their lives.

"The story then goes from non-linear to linear in the Signal Box Theatre and that reflects on the nature of the differing spaces, as the narrative goes from one place to another among the trains in the two halls but there's an order to it in the theatre space," says Damian.

"Part of the discussion surrounding doing a play at the NRM is thinking about what are the rules for narratives in a museum and what are the rules for a narrative in the theatre, and it's really interesting to see the similarities and great differences in the two ways of telling stories."

Katie likes the structure of the production that gives the audience free rein in the first half and draws them together – and the story together – in the second half.

"Our nature is to have a need to want to work things out and work out where something is going, so I'm intrigued as to what will happen when people have to see the different vignettes before going into the theatre," she says.

Damian suggests another question asked by the play is what stories do we choose to tell? "We tell stories in different ways: we do celebratory stories really well but we're less comfortable and brave when the stories have a 'pinch' in them and the demand is to be more introspective," she says. "That's when we have to have a good hard look at who we are, and our arts organisations have a duty to bring those stories to the surface, be it asbestos or George Hudson."

York Theatre Royal, Pilot Theatre and the National Railway Museum present In Fog And Falling Snow at the National Railway Museum, York, from tomorrow until July 11. Box office: 01904 623568