Drawbars necessarily posed a rollover risk depending on how the tractive torque was applied. Freight locomotives are normally designed to deliver high starting tractive effort and high sustained power. The bogies transmit tractive force through a central pivot. This gave newer locomotives increased heating and steaming capacity, which translated to higher tractive effort. These locomotives were equipped with trailing truck boosters, which raised their tractive effort by . The booster engine was an auxiliary steam engine which provided extra tractive effort for starting. Its driving wheels deliver of tractive force. A "tractive electromagnet" applies a force and moves something. Each operates with tractive effort and has a maximum speed of . The Centipede had an immense weight of and a starting tractive effort of 205,000 pounds. They are capable of generating of continuous tractive effort. In low-speed service where high tractive effort was critical, these Decapods were successful. All except 2901 had cylinders, giving a tractive effort of . Slip (also known as creep) is normally roughly directly proportional to tractive effort. The brief stipulated high route availability and high tractive effort.