Locomotives: understand how these assets operate

Rail transport makes it possible to move large loads over long distances more efficiently. The main advantage of this type of equipment is safety – as the incidence of theft and accidents when transporting cargo by locomotive is lower than in the case of road transport, for example.

According to data from the National Land Transport Agency, in 2023, the Brazilian rail transport network transported 531 million tons of cargo, representing around 390 billion UTK (useful ton kilometers). As such, the Brazilian rail network is still one of the largest in Latin America.

Types of locomotives

Locomotives are the railway vehicles that provide the power needed to keep trains moving. These assets can be categorized according to the energy source used to run them.

The most widely used type of locomotive for freight transportation is the diesel-electric locomotive, whose primary power source is a diesel engine. In other words, the engine is coupled to an electricity generator, which converts the engine’s rotational mechanical energy into electrical energy, which powers the electric traction motors that ultimately drive the wheelsets.

In this way, the electrical energy produced by the generator can be alternating or direct current. In locomotives that use alternators with DC traction motors, there is also a wave rectification stage.

This complex system is shown in the image below.

In some locomotives used for auxiliary operations in the rail yard, the diesel-mechanical system is also used. In this system, the diesel engine drives a set of gears, which are responsible for transmitting mechanical energy to the wheelsets.

Diesel-electric locomotive components 

Some of the most important components of diesel-electric locomotives are:

Diesel engine

This is the component responsible for transforming the chemical energy contained in diesel oil into mechanical energy to drive the electricity generator.

Generator

This component is driven by the motor shaft and its function is to transform the mechanical energy of rotation into electrical energy, which supplies the locomotive’s traction motors with electricity.

Traction motor

This is the component that converts electrical energy into mechanical energy and transmits it directly to the locomotive’s wheelsets via a pinion and crown system. It is driven by the main generator via electric cables and transforms the electrical energy into mechanical energy to rotate its axle, making the locomotive move on the rails.

Bogies

The bogies have the function of distributing the weight of the locomotive to the wheelsets and transmitting the traction and braking forces to the rails. These components also accommodate the traction motors and wheelsets, which are made up of an axle, steel wheels, a gear and bearings located at the ends of the axle. On the wheelsets, there is a crown, which is coupled to the pinion of the traction motor. In this way, the pinion rotates with its shaft and causes the crown to rotate, driving the entire wheel when the traction motor is operating.

Water, oil and fuel pumps

They are part of the cooling, lubrication and fuel injection systems, respectively, and operate around the diesel engine, being driven directly by it or by a dedicated electric motor, as is the case with the fuel pump.

Master controller

This is the component that houses the controls for the automatic brake, dynamic brake, manual brake, independent brake, reverser (sets the vehicle’s direction of travel), speedometer and horn.

In addition to these, other components such as fans, blowers, radiators and compressors work to keep the locomotive in healthy and safe operating conditions.

Locomotive traction motor failure

As already mentioned, this is one of the most important components of locomotives. Problems with the traction motor represent a considerable loss of efficiency for the vehicle. Some common traction motor failure modes are associated with wear in the coupling between the wheel crown and the motor pinion, which can usually be noticed by increased vibration.

In turn, abnormal vibration is a contributing factor to other faults in locomotives. Shocks and high-frequency vibration can cause serious damage to the crown-pinion coupling. In this way, deviations in the evolution of the pinion or crown cause variations in the rotation of the gears, which produces an increase in the load on the gear teeth and in the torque of the armature and runner shafts. In addition, wear on the bearings of the runner shaft is also a common cause of misalignment between the crown and pinion.

Faults in the insulation system of traction motors are also among the common causes of problems with this component. Insulation problems can lead to thermal degradation, contamination damage, abrasion or punctures.

Advantages of locomotive condition monitoring

By continuously monitoring the vibration and temperature of locomotive components, it is possible to identify trends in vibration levels and other signs of failure in advance. This prevents equipment breakdowns and reduces corrective maintenance costs. It also prevents the machine from being idle for long periods. Frequent monitoring of performance variables also improves equipment efficiency and maximizes its useful life.

Dynamox Solution for locomotive monitoring 

PitStop 

This is a solution for monitoring the condition of locomotives in “drive-in” format. Its aim is to reduce the inspector’s exposure to risk and to speed up data acquisition. In this solution, vibration and temperature data is collected using sensors positioned on the components while the locomotive is stationary for inspection. In this way, the waveforms collected allow a detailed analysis of the condition of the locomotive’s various components.

DynaTrigger 

This is a solution for monitoring the condition of assets in operation. The solution works on the basis of reading signals that represent a specific condition for vibration collection.

Count on the Dynamox Solution to monitor these assets and avoid failures, downtime and accidents. Contact us to find out more.