No. 18 is equipped with two single-lung Westinghouse air pumps... (not sure on the diameter).
She is fully up to date, as any engine operating today would have to be, to be compliant with the regulations as set forth by the Federal Railroad Administration.
She was built in 1920 @ the Cooke Works in Patterson, NY by the American Locomotive Company (ALCo). Air brakes were part of the equipment mandated by an act of congress in the 1890's. Enforceable as of Jan 1st, 1898, the "Railway Safety Appliance Act of 1893" mandated automatic couplers; power brakes, controllable by the engineer (in fact, I believe the act specified air brakes, as opposed to the British preferred vacuum brakes); and safety hand rails/grab irons... all items which railroaders today take for granted.
As for the need for a diesel, you need to bear in mind that an empty car today weighs as much as a fully loaded car from the time 18 was built. A fully loaded freight car today is stenciled at 286,000 pounds fully loaded, and it isn't unknown for a car to be overloaded by several hundred pounds. Most new cars today are designed & built for the eventual 300,000 axle loadings. The Barber S-2 truck is designed to take 150tons per truck, although in reality it will be several decades if not centuries before we see that type of loading, even on the mainlines.
Six full loaded freight cars clock in at (286,000 x 6 cars) 1,716,000pounds, or 858tons. A modern 130-car coal train tallies in at 18,000tons, which requires two 4,000hp, six-axle DASH-9's/SD-70M-2's to pull on the level. Add moderate grades and the horses required increases to 12,000hp on three six-axle units. Add in the grades around Altoona, and you are looking at 18,000hp on the head-end (2x 3,000hp SD-40-2's & 3x 4,000hp DASH-9's) and 12,000hp on the rear (4x 3,000hp SD-40-2's).
18's train that day weighed in @ 4.76666% of a modern coal train. Assuming the horsepower/tonnage ratio holds (Figured moderate grades, requiring a 2-unit, 6,000hp, helper consist on the rear), No.'s 18 & 111 generated 857.99999999999horses that day, combined. Subtract the 380hp from 111 and you are left with 477hp generated by 18, which I'm guessing is in the 65%-85% maximum design drawbar horsepower (HP's that actually make it to the coupler for real work).
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__ J. D. Gallaway __
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