The project originated at a ceremony that was held at Summit in July 2001. Two events were being celebrated: Historic Places Trust registration of the railway formation between Kaitoke and Cross Creek; and the Rail Heritage Trust of New Zealand award for restoration of two bridges on the route. Bob Stott, Editor of Rails magazine, commented that the formation was like 'a well-tended grave' and suggested that a railway of some shape or form ought to be reinstated.

The Wellington Regional Council's Landcare Committee invited rail heritage groups to explore how a tourist heritage railway might be reinstated on the historic Rimutaka Incline railway formation. The Rimutaka Incline Railway Steering Committee was formed in August 2002 to coordinate the project, drawing members from established rail heritage groups and the Upper Hutt City Council.

On 8 August 2003 the Rimutaka Incline Railway Heritage Trust was incorporated as a Charitable Trust, the culmination of months of planning and consultation by the Steering Committee. The Trust formally came into existence on 16 July 2003.

The Rimutaka Incline Railway Heritage Trust was registered with the Charities Commission as a charitable entity under the Charities Act 2005 on 27 February 2007, Registration number: CC10029.