Purdue University Agricultural Extension Service Lafayette, Indiana
Mimeo AE-52 March 1959
DUAL TRACTOR CONTROL
C. L. Hill, Agricultural Engineering Department, Purdue University Illustrated by Ralph Booher, Tippecanoe County Farmer
Part time additional tractor power can be obtained by hitching any two tractors together in tandem. With such an arrangement, one operator controlling both tractors has as much pulling power at his command as he would with a larger tractor.
Use of tandem tractors could be a boon to the many farmers who have expressed a need for more farm power. Since the average Indiana farm has three to five tractors, dual operation should involve little extra expense outside of that for larger plows and discs.
The same problems involved in operating single tractors are present in the tandem tractor unit but they require different solutions. These are such problems as controlling the clutch, throttle and hydraulic system of the second tractor.
The photographs on the following pages illustrate a method of controlling the throttle and foot clutch of a trailing tractor with a single acting hydraulic ram. This system allows the operator to control both tractors from the lead tractor without turning or reaching for any lever or knob. Figures 2-6 also show the attaching frame, ignition cut-off safety switch and the manual switch.
Advantages:
1.	The pulling power of the two tractors together is equal to or greater than the sum of their abilities as single units.
2.	When not being used in tandem, both tractors are available for work in their normal power range. A single, large tractor wastes fuel when used on light jobs.
3.	The major capital outlays are for larger plows, discs and hydraulic hose.
4.	Any two tractors regardless of make or model can be used; they do not need to be operated in exactly the same gear or throttle setting.
5. When a PTO machine is used, it overloads a single tractor. The dual tractor arrangement lets the front tractor do all the pulling while the rear tractor provides power for the machine.
Disadvantages:
1. More skill and care is required to operate two tractors in tandem than to control a single tractor.
some; considerations in using tractors in tandem