Two of the rarest tractors in the world will be among the stars at a spectacular event at the end of the month.

Already 350 tractors, including many pre-1930s, have been entered for the first Eastern Counties Tractor at Norfolk Showground and Heritage Spectacular on Saturday, March 31 and Sunday, April 1.

North Suffolk farmer and contractor Roger Desborough, who has more than 80 tractors in his collection, is a joint organiser of the event with enthusiast Graham Baldry, of Bungay.

“We want to bring together some really unusual and special tractors,” said Mr Desborough, who has brought machines from across the world to add to his collection.

They plan to collect the maximum number of Triple Does ever at a national event and have a goal of 25 machines. Three years ago, Mr Desborough, who has a Doe Triple D Dual Drive with serial number 351, visited Ireland when 14 Triple Does were assembled.

“I’m sure that we can do better at the showground,” he added.

Made by a farmer in 1958 who combined two Ford tractors to make a 100hp power unit, the idea was taken up by agricultural engineers Doe’s, of Utting, near Maldon, which went on make about 300 machines.

“It was the biggest tractor of the day when 50hp was a big machine,” he said. When their working life ended, often they were split and sold as two tractors for about �1,500, which explains their comparative rarity, said Mr Desborough, who has seen one make �60,000 at auction.

There will be a big show of early tractors, especially dating from the first three decades of the last century. This will include possibly half a dozen Peterboro tractors, built by Peter Brotherhood at nearby Eye in the early 1920s. One of the earliest Ivel tractors, made by Dan Albone at Biggleswade, near Bedford, dating from about 1903, will also be present.

Mr Desborough, of Church Farm, Wenhaston, near Halesworth, is bringing another gem. It is a Saunderson Universal Model G, made in Bedford in 1917.

They’ve had tremendous support from fellow enthusiasts including the Starting Handle Club members, who will be bringing a selection of popular makes as well.

Mr Desborough’s special American tractors include one of the only half a dozen Prairie tractors, dating from 1916, and only surviving Caterpillar tractor used to build the giant Hoover Dam. A leading contractor, Henry J Kaiser, which was building the dam in Arizona and Nevada between 1931 and 1936, wanted four heavy-duty diesels from Caterpillar. Mr Desborough acquired this machine, fitted with a 24-litre Atlas marine engine instead of the usual underpowered Sixty petrol version.

Weighing 12 tons, this giant was used to build the New Orleans levees, said Mr Desborough. His Polish skilled fitter, Jasek Kobelia and self-employed engineer Chris Napthine are doing restoration work on it.

The Twin City Prairie Tractor 65/40 cost about $4,200 and weighed 13.5 tons or 23,700 lbs. It was 10ft 6ins wide and had a turning circle of 21ft 3ins and could pull an eight or even ten furrow plough to a depth of 14 inches. With his late son, Thomas, they brought the machine back from Missouri a few years ago. “That’s the only one outside America where there’s only about six or seven left. Why they let it come out, I don’t know but they did,” he added.

Mr Desborough, 66, who farms about 350 acres and was born on the farm, took over from his father, Ralph. He came from the Wisbech area as the second world war was looming, and in late 1938 moved by motorcycle to take the farm, then extending to about 80 or 90 acres. His son diversified into the haulage business, which is being wound up later next month.

He has always been fascinated by tractors, and started with two Fordsons in the 1960s. “The first tractor that I had was a Fordson E27 N,” he said. Then he got a Fordson N, then added several Field Marshalls.

He has always liked early and rare tractors. “I like these English tractors such as the 1923 Vickers of Crayford,” said Mr Desborough. At that time, English tractors such as the Saunderson cost about �500 when the Americans sold rivals for �120. He also has a couple of diesel Austin tractors, which are as “rare as hen’s teeth.”

His early post-war Lanz Bulldog road tractor, which is capable of about 40kph, has been fully restored to its original colours. Mr Desborough also has one of the last 300 Lanz tractors, made after John Deere had acquired the Mannheim factory in Germany. Even John Deere doesn’t have this model in its collection.

He has one of the earliest Case L crawlers and several Minneapolis Moline tractors including the MM England UDM Model made in 1946. Although many of tractors are pre- war, he also bought a 1965 Ford Northrop. Although about 100 to 150 were made, they’re quite a rarity.

Mr Desborough, who brought another early Peterboro back from Australia, is also hoping to have half a dozen at the showground. He is bringing one of the only two British Wallace tractors in the country, including one lent from Paul Rackham’s huge collection at Roudham, near Thetford.

Entry from 10am to 4pm, adults �6 on the day, children free. Details via galbdry@hotmail.co.uk or by calling 01986 895133.