For link club chairman David Wills last year’s UK launch of the innovative electric drive D7E, was particularly special, as he is familiar with the original Caterpillar^® D7E model, launched 50 years ago.

Known as the D7E 47A series direct drive tractor, the original was launched by Caterpillar in December 1961, decades before the new electric drive transmission version. Explaining the history of the original D7E David Wills said: “The original D7E replaced the17A series D7C / D7D, which had been in production since 1955 with over 19,400 tractors in use around the world. The tractor had many new features including oil immersed steering clutches, oil cooled brakes, console mounted steering controls, 300 mm longer track frame with 6 bottom rollers and sealed pin and bushes on the tracks.

“What was interesting about the original model is that it shared the same turbo charged D339 engine generating 160 fly wheel horsepower at 1200 rpm as the D7D. From a weight perspective, the base tractor weighed 16 tonnes, which compared to the new D7E, weighing 27 tonnes, shows the weight difference between the two units.”

“When you look at the research carried out at the time, the comparative dozing tests established that the direct drive tractor was 20% more productive than the old D7D and this advantage increased to 40% once the 48A power shift transmission version was released in 1965. The power shift eventually out sold the direct drive by two to one, even allowing for the much shorter manufacturing period, with over 9,500 48A’s produced compared to just 4,600 47A’s.

“This tradition of increased productivity with the launch of every new Caterpillar model continues to this day, as the new D7E can itself move 10% more material than the D7R series 2 model that it replaces. On top of this, the new model comes with a grade system that also helps to boost productivity, making both units stand out as performance enhancing models of their time.

“From a UK perspective with fuel savings and productivity benefits, the D7E makes an attractive buy, particularly in the waste sector. However when launched in 1961, the original was less attractive, as the strong dollar exchange rate caused only a limited number of D7E’s to be imported.

“This was challenging for the market at the time as there was a definite need for a D6 / D7 sized tractor due to the large gap been the D4C and the D8H models, which were being built in Glasgow. This issue was resolved when Glasgow started to produce the 120 fly wheel horsepower D6C in 1965.”

Replaced in 1968 by the updated D7F series today, a number of D7E tractors can still be found in the UK. The majority of these units are the 47A direct drive variant, as these tractors were commonly used for agricultural operations. Several have been preserved by Link Club members and are still used regularly on their farms for cultivation work or for bulldozing duties.

The 47A tractor, pictured was manufactured in 1963 and has just been restored back to its new condition, a true testament to the ‘Lastability’ of Caterpillar equipment. Originally fitted with a cable controlled 7A angle blade, the D7E is now fitted with a 7S straight angle for its current role with a Cambridgeshire based contractor.

For more information on the new D7E visit www.cat.com/d7e

To view a video of the D7E in action on Lastability click onto http://www.lastability.com/index.php/vids/262-cat-d7e-in-action-extended

To visit the Link Club photostream on flickr click here