National Railway Museum, York

If you type the phrase "search engine" into Google you come up with over 300 million hits. A search engine is a program that locates information in a database. It is also the clever title of the latest development at the National Railway Museum (NRM) in York.

Search Engine opened in December and had its official launch at the end of February. It represents the first phase in the long process of bringing the museum's archive collection out from deep storage, all 180 tonnes of it.

This includes 1 million engineering drawings, 1.5 million photographs and 2,000 artworks, plus the archives of the museum itself, both before and after its various collections were merged to form the NRM in 1975.

One of the best things about Search Engine is its location. The first glimpses you get are via a couple of portholes in the wall of the Great Hall. By pressing a button, the view into the stores is revealed. An accompanying interpretation panel entitled Active Archive explains the goal of Search Engine: "to bring the secrets of the archives out into the public domain."

Search Engine is actually located directly above these stores, on a balcony overlooking the Great Hall. The first thing the visitor sees is a small exhibition called What's in Store. It features examples of the types of things that will gradually start to become available via Search Engine.

The straightforward display is devoid of costly interactives that would have only drawn attention away from the fascinating selection of paintings, books, letters, photographs, posters and journals.

The first object on display comes as a bit of shock. Nice painting, but where's the train, I wondered as I looked at Claude Buckle's lively depiction of a boat race off the coast at Ryde.

All too often labels next to paintings are an uninformative distraction. But not this one. It told me exactly where to find the train: for in the middle distance, ploughing through the painted waves, is a railway ferry.

After looking at this painting, I consulted the Public Catalogue Foundation's volume for North Yorkshire available on one of the open shelves. There I found out that Britain's railway companies were once "the largest operator of docks and wharves in the world" - which explains why the NRM has so much maritime art in its collection.

This discovery is presumably exactly the sort of thing that Search Engine is designed for. The decision to begin the inaugural exhibition with Buckle's painting is therefore a smart one. Search Engine is just like that railway ferry in the painting: a big container with all sorts of train-related things hidden inside waiting to be unloaded.

These secrets include the objects bequeathed to the NRM by the sound engineer and railway enthusiast, Peter Handford who died last year. Some of them feature in the What's in Store exhibition, such as a photograph of Handford recording steam engines as they puffed past.

These were sold on vinyl LPs, examples of which are on show. This and other sounds (including an important oral history archive) will soon become available to be ordered from the store and listened to in Search Engine's sound booths. Alongside them are larger glass cubicles with desks for people who want to research with less distraction from the hubbub coming from the Great Hall below.

But the Great Hall is likely to come as a welcome diversion. When the busy researcher gets tired they can look down and see iconic railway engines clustered around the huge turntable. As I sat writing this review there was a demonstration of how the turntable works, to the delight of the many children present.

Fully accessioning all the objects in the NRM's archive will take many years. And the vital importance of documentation is emphasised in another object on display. It is a drawing for a passenger carriage from the 1860s. The label alongside says that it has been in the collection for over 100 years. But no one knows what it actually represents or who drew it.

By encouraging people to use its archives, it will surely be just a matter of time before some enthusiast discovers the provenance of the sketch and feeds that information back into Search Engine. This will help others in their research - and so it goes on.

With this in mind, the decision to call it Search Engine is brilliant. I became even more convinced of this while leafing through Alan Jackson's Railway Dictionary (2000). It reveals that "searchers" was an old name given to railway workers who went through the carriages at the end of the day looking for lost property or damage.

Maybe some of the things they found ended up in the NRM's archive and are waiting to be discovered by the "searchers" of the 21st century. The NRM is a copybook example of a museum that strives to provide access to as many objects as possible to as many people as possible.

Search Engine is the archival equivalent of the Warehouse, the NRM's open storage collection on the other side of the hall. Together they represent the NRM's attempt to challenge "the perception that museums all have reserve collections locked away with no practical use to the public".

Looking down from Search Engine at the hoards of children on half term holiday in search of Thomas the Tank Engine made me appreciate that the NRM caters just as much for them as it does the most hardcore of train enthusiasts wanting to research some very particular aspect of railway history.

This wholehearted approach to access combined with great collections, free entrance and enthusiastic, helpful staff means that the NRM promises to live up to the slogan of Indiana Harbor Belt Railroad that I found in Dow's Dictionary of Railway Quotations: "Proud past, bright future."

Stuart Burch is a lecturer in museum studies at Nottingham Trent University
Project data

Cost: £4m
Funders: Heritage Lottery Fund (£995,000), Higher Education Funding Council for England (c£1.5m), Department for Culture Media and Sport; University of York
Architect: Danton Elgee
Principal contractor: Ellmore Construction
Project management: Turner
and Townsend
Racking: System Store and Nordplan