Ballast

Process locomotives are designed to produce the maximum amount of tractive effort. Since tractive effort by definition is machine weight multiplied by average adhesion then the first step to maximize the machine weight. For 40 inch diameter rail wheels the AREA recommends a limit of 33,000 lbs. per wheel. We ballast the four axle units 40 inch diameter units to 135 tons or 33,750 lbs. per wheel. This is only 2.3% above the recommended loading and it is the same as for most road switchers in service today on the Class 1 and short line railroads. Most six axle locomotives have 42 inch diameter rail wheels. AREA allows 34,900 lbs. per wheel. This equates to 209.4 tons of locomotive. We ballast the six axle units with 42 inch wheels to 210 tons and the six axle units with 40 inch wheels to 200 tons. By maximizing the machine weight yet not exceeding the proper wheel loadings the result is the maximum tractive effort without damaging the plant track system.

There are several ways to add ballast to a repowered locomotive. These include concrete, concrete filled with scrap metal, scrap metal in metal boxes, leaving the existing locomotive engine and generator in place for ballast as is or by boxing them in. The process locomotive uses steel billets and plates welded into place. The billets are cut and fitted into the center of the frame and under the cab floor. Large steel plates are welded to the top of the frame inside the hood area and in the front of the hood area. By custom fitting and welding the billets and plates into place it strengthens the frame and makes balancing the weight between the trucks within +/- 1000 lbs. easy to do. Inside the cab a concrete cap is poured over the billets in order to make a smooth cab floor. A non-skid rubber matting is then secured to the concrete floor.


Steel Ballast Plates Welded to Top of Frame Inside the Hood Area	Steel Ballast Plates Welded and Stacked In the Nose of the Locomotive