Operations Illustrated: Running the Rails
Gary Yelvington is the president of Conrad Yelvington Distributors and a vice president within Oldcastle Southern Group. He received a four-year scholarship to play football at the University of Alabama, where he graduated in 1977 with a bachelor’s degree in business administration. Yelvington joined the family business and helped transform the trucking company into a rail distribution powerhouse. The company was acquired by Oldcastle Materials Group in August 2007.
Bob Domnick, P.E., is the vice president of sales, marketing, and engineering for Superior Industries, LLC. He received a degree in agricultural engineering, as well as a professional engineering degree in mechanical engineering, from South Dakota State. In 1997, he served as the lead designer on the company’s telescoping conveyor. He is a frequent speaker at meetings and is a board member of the Conveyor Equipment Manufacturers Association.
VOICES OF EXPERIENCE
Moving material efficiently is the name of the game at Daytona Beach, Fla.-based Conrad Yelvington Distributors, a part of the Oldcastle Southern Group. According to Gary Yelvington, president, the company has moved as much as 10 million tons per year of aggregate during peak production years.
“The Federal Railroad Administration has determined and classified our railroad operation as a Class 3 Industrial Switching Company. We are compliant with hours of service regulations, along with many other sections of the transportation code,” Yelvington says. “Simply put, we can do a lot of things that not many folks do in our industry.”
Typical rail movement of aggregate includes unit trains with a minimum of 75 cars and as many as 100 cars. The company owns or leases more than 1,300 rail cars, which includes about 40 gondola cars, but most are bottom-drop cars.
A bucket-type machine — typically an excavator — is used to scoop material out of the gondola cars into trucks. “We do some of that, but it’s only for the big rip rap material that you can’t drop through the bottom of a car,” Yelvington says.
For peak efficiency, however, Yelvington explains that he prefers the bottom-drop cars. “Most of our cars are bottom-drop cars,” he notes. “Those are the fastest cars to unload, but you have to have infrastructure to unload those types of cars.”
When a train is unloaded at one of the company’s yards, a cut of approximately 15 cars is pulled across a pit by one of its locomotives. Yelvington says the company has about 35 locomotives, with second units at its busiest sites to allow for maintenance or breakdowns.
Workers open the doors on the bottom-drop cars, and the material falls into an underground hopper where it is discharged onto a feed conveyor that carries it up at about a 15-degree angle along a path that leads a couple hundred feet away from the track. Material is then discharged onto a radial stacker, which has a 270-degree arc. The stacker is used to stockpile material into various sizes.
“Depending on the product, we unload 12 cars per hour,” Yelvington says. “If it’s base or screenings or a fine product, it might be 10 cars per hour. If it’s a coarser material that flows and spreads freely, we might do as many as 14 per hour.”
Bob Dominick, PE
With big money on the line, many producers moving material by rail are becoming increasingly savvy about how little changes in the process can improve overall metrics. “In the past, I think there just had never been a study of process flow for rail unloading,” says Bob Domnick, vice president of sales, marketing, and engineering for Morris, Minn.-based Superior Industries, LLC. Factors such as the size of the hopper and the mix of rail cars sometimes vary widely, which can lead to inefficiencies in the process.
“It seems to me that, in the past, operators would build pits with as big of a hopper as they could,” he says, noting that size would be the maximum available, based on the site’s water level to ensure that pumping would not be necessary. “By and large, there would have been several hoppers and then a conveyor under those hoppers.
“Today, simplicity is chosen, so if a single hopper with one discharge point under that conveyor can be done, that’s what is chosen because you don’t need as much depth to accommodate the conveyors,” Domnick says. “That way, the operator doesn’t have another drive to maintain, which can be a headache.”
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