(Bloomberg) -- Caterpillar Inc. shares tumbled in premarket trading after the company said its order backlog shrank in the third quarter, in a sign of slowing demand for its iconic yellow machinery.Most Read from BloombergSaudi Forces on Alert After Clash With Iran-Backed HouthisInnovent, Lilly Obesity Drug Spurs More Weight Loss in TrialIsrael Latest: Netanyahu Vows to Stay On; Targets Hit in LebanonSony’s Bungie Game Unit Cuts Staff Following Delayed TitlesApple Unveils New Laptops, iMac and T