>>914006Huge firebox and "superpower" rear trucks are for high horsepower...which is only at high speed. As my previous post states, tractive effort is what you want in low speed operation, and tractive effort is what determines tonnage rating. 2-6-6-6 had only 110,000lb tractive effort, compared to an N&W Y6b 2-8-8-2 putting out 127,000 simple, 166,000 starting, and the Virginian 2-10-10-2 putting out 147,000 compound, 176,600 starting.
