The power systems of locomotives in the US are usually diesel-electric and will vary between single and double bearing generators (this refers to the number of bearings in the generator that the engine is driving). A single bearing generator has one bearing at the non-drive side of the generator shaft, and the other side of the shaft is directly connected to the engine flywheel or flex-plate. A double bearing generator has a bearing at each end of the shaft and is connected to the engine via a torsional coupling. Locomotives operate in various environmental conditions, including tunnels. This poses many challenges for the power system, especially for the engine crankshaft damper and torsional coupling.
The Geislinger steel spring damper is an all-steel design that receives pressurized oil from the crankshaft. This pressurized oil not only provides high damping in the system, but also regulates the temperature of the damper ensuring constant performance in all operating conditions, see Figure 1.
In North America, Geislinger provides dampers for engines that are operating on freight locomotives using single bearing power systems. If the damper fails, the power system will fail, and the locomotive will be out of service. The damper is a very critical component for the system’s overall success, but has also enabled engines to meet stricter engine emission targets. The damper’s function is to reduce torsional vibrations in the engine, resulting in lower stresses for components in the power system. As the emission targets increase, the torsional load in the damper steadily increases. The Geislinger steel damper’s robust construction has allowed the damper design to remain the same through each of the emission tiers, offering the same performance regardless of the tier level of the engine. The reliability and performance of the Geislinger damper allows freight locomotive operators around the world to keep to their schedules, supporting the international trade. Geislinger dampers not only optimize the engine, but they also help diesel engines to operate in a more environmental way.
Double bearing locomotives use a torsional coupling to couple the generator and engine. The types of locomotives that use this power system with Geislinger couplings like in Figure 2 include Switcher, Rail Yard, and passenger train locomotives. The couplings for these types of systems must be compact, robust, and also be able to handle extreme environmental conditions.
The locomotive market is a demanding industry that requires a highly engineered product that can handle all dynamic conditions. Due to the experience in the industry, Geislinger proves to be a well trusted partner in providing torsional solutions for locomotive applications.