Testing Grantham’s greatest invention

The Grantham Machine That Invented the Caterpillar Track

Long before Caterpillar became one of the most famous names in engineering, the idea behind it was born here in Grantham. In the years before the First World War, Richard Hornsby & Sons built and demonstrated what was, in effect, the world’s first practical tracked vehicle. It worked, it astonished the public and the Army, and then, unable to sell it, the firm let the invention slip across the Atlantic to an American rival whose name it would go on to make world famous.

Hornsby & Sons was one of the town’s great engineering firms, a well-established maker of oil engines and agricultural machinery. The crawler track itself was the work of David Roberts, the company’s chief engineer and managing director, who patented his “chain track” design in 1904. Instead of running on wheels that sank into soft ground, Roberts’ machine laid its own continuous track of linked plates beneath itself, spreading the weight and letting it cross ground that stopped conventional wheeled tractors dead.

Roberts began showing the machine to the British Army’s Mechanical Transport Committee from around 1905, and a formal demonstration at Grantham in February 1906 saw the crawler comfortably outperform a wheeled tractor. Improved versions were then tested at the Army’s headquarters at Aldershot, and it was there, in 1908, that the Hornsby crawler had its finest hour: a demonstration attended by King Edward VII himself. Hauling a trailer with a dummy gun aboard, the tractor climbed banks, crossed ditches and shrugged off rough ground, and the display became national news. The Army bought a small number of machines, with four heavy-oil tracked tractors delivered to the War Office by 1910, but the orders never grew beyond a trickle.

For all the admiration, the crawler simply never found a market. Roberts had spent around five years developing it and, by his own account, barely covered his costs from the fees the Army paid for trials. Neither military nor civilian buyers came forward in the numbers the project needed, and by the end of 1913 the firm had grown thoroughly disillusioned with an invention that had brought prestige but no profit.

Shortly before the First World War, Hornsby sold the chain-track patent rights to the American Holt Manufacturing Company for £4,000. Holt would later become the Caterpillar Tractor Company in 1925, after merging with the C. L. Best Tractor Co. The name itself traces straight back to those early trials: “Caterpillar” was reportedly coined by onlookers who said the tracked machine crawled like a caterpillar, a remark variously credited to a Holt photographer and to watching soldiers. Benjamin Holt registered it as a trademark in the United States in 1910.

The final twist is the hardest for a Grantham reader to swallow. Within about a year of buying the patents, Holt found the market Hornsby never could. With the outbreak of war, the War Office ordered hundreds of tracked tractors to the Holt design, and many were built here in England under licence. Hornsby’s near neighbour and rival, Ruston of Lincoln, turned out 442 of them. The Hornsby crawler is also widely credited as an important ancestor of the tank, the weapon that would come to define the Western Front.

One of those original Grantham-built machines survives today at The Tank Museum in Bovington, where it is the oldest vehicle in the whole collection. It stands as a quiet monument to a Grantham invention that got there first, and then watched the future roll away on someone else’s tracks.