Covered Hopper, ACF PD 3500 Flexi Flo

History: Built between August 1964 and June 1966 the American Car & Foundry (ACF) 3500 cu. ft. covered hopper was an early innovator in pressure differential unloading and a marketing masterclass thanks to the “Flexi Flo” tag coined by the car’s biggest customer, the New York Central railroad.
New York Central specified a car with a 315,000 pound gross weight (315K) to take full advantage of the heavy-duty capability of its core mainlines. The cars had a load limit of 245,200 lbs., allowing them to hold six truckloads of product each – a critical factor when trying to win business back from the highway. The specific gravity of powdered cement dictated a 3500 cubic foot capacity. To emphasize how far ahead of the times NYC was consider that the standard railcar gross weight was 220K, there still isn’t a national 315K network in 2020 and some short lines and regional railroads are still struggling to get their bridges upgraded to 286K.
The cars were delivered to NYC in four batches as outlined in the roster below. They each differed slightly from each other. The most obvious spotting characteristic were the vertical side ribs on the first batch of 25 cars. One has to look closely to spot the differences between the next two lots. The final NYC group was made up of five 3600 cubic foot tank type covered hoppers built for BF Goodrich. They are included for reference but are a totally different car design.

Railroad/Company: ACF Industries LLC originally known as The American Car and Foundry Company and was formed in 1899. In 1955 ACF Industries, Incorporated became the new name for The American Car and Foundry. Over the years railcar manufacturing and leasing were the major forces in ACF's economic growth and stability. ACF has weathered many changes and is still committed to the manufacture of new railcar and railcar parts and sub-assemblies. ACF Industries LLC became a successor to ACF Industries, Incorporated on May 1, 2003.

ACF Industries LLC is a leader in the manufacture and fabrication of specialty railcar parts and miscellaneous steel products. While the Company's primary purpose is to compliment the new car and repair car market, it also provides manufacturing support to other manufacturers of steel products.

ACF Industries LLC is headquartered in St. Charles, Missouri and our manufacturing facility is located in Milton, Pennsylvania.

From the company website.