Twin 671 Detroit Engined 18Ton Chamberlain Tractor, 12 wheels put the power to the ground, it pulls a Shearer 62ft wide seeder, 105 sowing rows, 6Ton of seed and super, sowing 55 acres per hour at 7mph. The two tractors engines are identical to the 671 Detroit "General Grant" tank engines, This monster makes short work of the huge acres that are Typical of modern Australian broad-acre farming. This clip was cut from the O-Line Video/Media file tape.