Here's the real thing. Meaning ‘without parallel’, Sans Pareil was built by Timothy Hackworth in 1829 to compete in the Rainhill Trials organised by the promoters of the Liverpool to Manchester Railway. © Jon Pratty, 24 Hour Museum

The National Railway Museum (NRM) in York has acquired what it believes to be a priceless model prototype that could prove to be the 'missing link' between early railway engineering and all modern engines.

The working model, known as the Sans Pareil (Without Equal), dates to the early nineteenth century and is one of the oldest model steam locomotives in the world. It was acquired recently by the NRM with the help of lottery funding when the British Engineerium in Hove, Sussex was threatened with closure.

Originally thought to have been built by Timothy Hackworth as a prototype of the Sans Pareil steam engine that took part in the Rainhill Trials of 1829, experts at the museum now think it may be far older.

In fact evidence suggests that it may have been designed by the grandfather of the railways himself, Richard Trevithick.

"This may be one of the first model railway engines in the world - but this model was not built as a toy. It was to test new engineering concepts,” said Jim Rees, Rail Collections Manager at the National Railway Museum.

"The Sans Pareil model is very different in design to Hackworth's locomotive of the same name which took part in the 1829 Rainhill Trials. But we know that Trevithick used the same name in his own early work.”

A replica of Sans Pareil steams down the line at Locomotion, the NRM's north east outpost, in 2004 watched by Andrew Scott, left, Head of Museum, NRM. © Jon Pratty, 24 Hour Museum

“If this is indeed Trevithick's work,” he added, “it is one of his earliest designs, experimenting with the working relationship between two cylinders. It could be a very exciting discovery indeed."

Trevithick is famed for building the world's very first steam locomotive, the Penydarren, in 1804 and is also credited with the engineering advances that made locomotives small enough to be able to pull carriages, laying the foundation for the modern railway system.

Specialists at the National Railway Museum suspect that Sans Pareil may be one of his earliest working prototypes, when he was experimenting with a double-cylinder boiler for the first time.

If their theories prove to be correct, the model could be said to be the forerunner not only of the modern railways but also of virtually all modern engines, including cars and aeroplanes.

The model, which was purchased by the Museum from the British Engineerium in Hove for just over £92,000 will go on display at the NRM from Monday July 10 until September 2006. It will then be despatched to laboratories for analysis by scientists and historians who will examine the model's design and manufacture in detail.

It is hoped that by analysing the metal used in its construction scientists will reveal where the model was built and provide clues as to its origins. Engineers will also compare the model's design with other machines from the 1800s, and investigate its machinery marks.

The Great Hall at the National Railway Museum © National Railway Museum

Another clue may be found in the fact that Trevithick was interested in whether steam locomotion would be effective at high altitudes, so the model may also have visited Peru for experiments in the Andes. An analysis of boiler residues may reveal whether Peruvian water was ever used in the model.

Dr David Gwynn of Govannon Consultancy is an industrial archaeologist commissioned to inspect the model for the Museum. He agrees that the early signs point towards a Trevithick design: "The double immersed cylinder on Sans Pareil resembles other locomotives by Trevithick and is similar to those used around 1811,” he said. “That particular design concept was never used by Hackworth."

The findings of the investigation will be presented at the 2008 Early Railways Conference in London, following which, the model Sans Pareil will go on public display at the museum in York. Although small in comparison to some of the giants of steam held by the museum, the little model may yet prove to be one of their star exhibits.

The purchase of the Sans Pareil for the National Collection in York was made possible by a £51,000 grant from the Heritage Lottery Fund and a £30,000 donation by the Friends of the NRM.