In our return to this occasional series on machines that have worked above and beyond the call of duty, Emily Padfield talks to James Wright about his family’s Caterpillar D4 crawler.

• When did you buy it?

We bought it secondhand about 25 years ago. Before it came to us, we think it had been part of the Ground Nut Scheme, a project to plant an area equivalent to the size of Yorkshire in East Africa with groundnuts (or peanuts). It was the biggest scheme of its type, but the soil type meant that the plants wouldn’t grow and the whole thing was a disaster.

• How many hours has it done?

6,370 – but that isn’t much for one of these. They were the first tractor units with an hour meter that could go over 100,000. We’ve heard of one that’s done 120,000 – that’s 13.7 years. Cat started making them in 1937 and the first ones, like this, had a petrol donkey engine to start the main engine. We think this one is about 60 years old.

• Why did you opt for this machine?

My father collects Caterpillars and has a couple of D4s, D6s and even a D8. The others have done equally as many hours, if not more, but it’s hard to see the hour gauge clearly enough. When people bought these machines back in the 1950s they never needed to buy another machine, they simply don’t wear out.

What are its main tasks?

Because it’s fitted with bulldozer blade site levelling, woodland clearance and track maintenance are its main duties.

• Where’s it kept?

It’s always kept in a shed, and lives next to another D4 and a D6.

• Who drives it?

Mostly my dad but my brother and I have both driven it over the years.

• How well do you look after it?

It gets the same treatment as everything else – so the usual servicing and oil and water checks.

• What major problems have you had with it?

Literally none.

• What’s the best thing about the D4?

It does its job very nicely – and it’s unbeatable for breaking up concrete. It’s also never broken down. Although we’ve not done a colossal number of hours – we’ve done a fair few and it’s not let us down once.

• What modifications have you made to it?

It came with a pto shaft and because we knew we wouldn’t use this model for any draught or pto work we took it off and put it on the other D4 we have. We’ve actually put the fertiliser spreader on that one when it’s been really wet and nothing else would travel on the soil.

• Is there anything you would change about it?

Apart from a more comfortable seat – no. We don’t need air-con as it doesn’t have a cab, although I wouldn’t want one for what we do with it.

• What’s the fuel consumption like?

It has a small engine, not like the machines these days. The tasks we’ve had it on haven’t proved to be too demanding on fuel.

• When or if you come to change it – what would you go for?

We would never change it – wouldn’t need to.

• What’s your overall machinery replacement policy?

Machinery traditionally has always lasted a long time, according to my dad. But modern machines are now so sophisticated that they’re not designed to run for as many years as they used to. Anything mechanical my dad can fix, but electrical stuff – no way. Electronics don’t like him and he doesn’t like them.

• How easy is it to get spare parts?

If we ever needed anything we would go to Finnings as they still stock all the parts, even for older models. But we haven’t needed anything in the 25 years we’ve had it.

Caterpillar D4

• Hours: 26,370

• Age: 60 years

• Power: 43hp

• Engine: Four-cylinder Caterpillar

• Transmission: 5F/1R dry disc transmission

• <B>Have you got a machine that’s done a lot of hours? It doesn’t have to be vintage; it could be the main tractor in your fleet that’s done 15,000 hours in five years. Tell us about it by emailing emily.padfield@rbi.co.uk or calling 020 8652 4901.</B>