Dear Bedford,—Speaking roughly, a freight-engine of the "Consolidation" type (eight driving-wheels and two truck-wheels) weighs from forty-seven to forty-eight tons of two thousand pounds. On a road with no grades over twenty feet to the mile (1 in 250) it will haul over one thousand tons at fifteen miles an hour. If the train is of merchandise, it will be of say fifty cars, each weighing ten tons and carrying ten tons. If it is of coal or ore, the cars will each carry twenty or twenty-five tons.
["The 'Rocket,'" said Bedford, "which was the successful engine at the Rainhill competition, weighed a little over four tons and had four wheels. Dragging a weight of thirteen tons in wagons, it made thirty-five miles in about two hours.">[
Our Engine No. 2 [continued the letter] made a mile on a level in forty-three seconds with no train, but there are very few such records. Two of our fast trains (four cars each, weighing twenty-five tons) make a schedule in one place (level) of nine miles in eight minutes. I have seen a record of a run on the Bound Brook route of four cars, ten miles in eight minutes. I think this must have been down hill.
I hope these facts will answer your views. If there's anything else that I can get up for you, I shall be glad to do it.
Yours truly,
Prentiss Armstrong.
XI.
ELI WHITNEY.
The young people all came in laughing.