Industrial Internet of Things powers today's locomotives

06/26/2019

A train drawn by several locomotives can transport 500 miles of cargo on a gallon of fuel. What makes this efficiency possible? The sensor network is distributed over the locomotive and the car behind it. Today's locomotives have up to 250 sensors that can read thousands of readings per minute. Modern locomotives are basically rolling industrial power plants, and like all modern power plants, they benefit from the Industrial Internet of Things (IIoT) technology.


General Electric ES44DC locomotive

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Figure 1: The GE ES44DC locomotive is a fully automated industrial diesel power unit on wheels that produces 4,400 horsepower (3,280 kW). The 250 sensors continuously monitor the engine and the environment, automatically controlling the throttle and brakes. (Source: Wikipedia)


The main focus of the Industrial Internet of Things (sometimes referred to as Industry 4.0) is to increase efficiency by automating existing processes as much as possible. Industrial automation has been rapidly adopting any new technology that can increase efficiency. For example, a programmable logic controller (PLC) replaces the row and row relays. Proprietary wired communications were replaced by Ethernet, and Ethernet was quickly replenished. Application-specific embedded system code was replaced by Microsoft Windows, and in some cases, Android or iOS is now being replaced or supplemented. The custom CRT console was first replaced by a desktop computer and replaced by a laptop, and is now being replaced by a mobile tablet that is connected to the system for remote management via Bluetooth. Imagine using a tablet to start or stop a 200-ton train!


Modern manufacturing and power plants using IIoT

The Industrial Internet of Things is now the latest technology to revolutionize modern factories. The most important benefit is the increased operational efficiency of manufacturing facilities and power plants, which has been the focus of early adopters. For example, by automating some of the cumbersome processes that have been performed by human operators in the past, manufacturers can significantly increase efficiency while reducing errors. Another important use of sensors and the Internet of Things is predictive maintenance. This involves monitoring various components of the plant or power plant to determine if the component is close to failure. This allows components to be replaced before failures occur in the operating environment, thereby avoiding high downtime costs. Just through these two apps,


Industrial automation has relied on sensors to measure pressure, fluid flow, temperature, vibration, position, position, presence, and more. These sensors are now being implemented with greater precision and lower cost, as recent advances in sensor technology allow sensors to be battery powered and wirelessly connected to the host system. This allows for more flexible connection of sensors while reducing the cost of the sensor network.


Modern diesel locomotive and IIoT

Today's locomotives are a true example of extreme industrial automation. Modern locomotives use a diesel engine to drive an alternator for AC current, or a generator for driving a DC current that powers the electric motor that drives the wheels. A prime example is the Evolution locomotive made by General Electric (GE). These locomotives have more than 250 sensors in the engine, cab and surrounding area. These sensors send more than 150,000 real-time data points per minute over the network. The processed data includes engine temperatures at various points, including bearing and manifold temperatures, oil pressure at various points in large diesel engines, train speeds, and more. Cameras on the front of the train and around the train are sent to a computer to identify problems or obstacles. External sensors measure weather, including air pressure, wind speed and direction, temperature and humidity. The condition and inclination of the track were also measured. The computer also controls auxiliary systems such as fans, lights, horns and cabin air conditioners.


Engine Engine Sensor Display for GE Evolution Series Locomotives

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Figure 2: Engine compartment sensor display for the GE Evolution series of locomotives. More than 100 sensors are displayed on the panel, including the precise air/fuel mixture and exhaust gas components in the cylinder. (Source: YouTube)


Continuous monitoring of engine status through real-time data enables full and precise automation of the locomotive, including automatic throttle control and braking. For example, Figure 2 shows how an engine sensor measures precise fuel-air mixing so the computer can adjust the mix for maximum efficiency. This level of measurement and control helps automate the entire train operation with minimal human intervention.


Engine Engine Sensor Display for GE Evolution Series Locomotives

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Figure 3: Block diagram of a modern diesel locomotive (Source: Wikipedia)


Given the close relationship between modern automation plants and today's automated locomotives, it is not surprising that today's locomotives are controlled by some of the same PLCs used in today's factories. Ethernet is used as the backbone of the train VLAN network and supports Modbus TCP / IP. Many sensors are assigned a local host IP address, and the entire train transmits data to the railroad's cloud via radio and 4G networks. Industrial cell phone routers communicate from Phoenix Contact via a telephone network and are qualified for rail use.


Mobile router

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Figure 4: Mobile phone router for wireless communication between the locomotive's VLAN and the railway headquarters (Source: Phoenix Contact)


The bus interface of the PLC includes Ethernet EGD, Genius, DeviceNet and Interbus-S. FieldBus interfaces are popular because they are easy to use and are therefore common in industrial environments. The PLC on many GE locomotives is the VersaMax Industrial PLC from Phoenix Contact. They can be snapped into the main DIN rail trunk or easily screwed into the cabinet panel.


Modern locomotives also use single-board computers (SBCs), which use the popular COM Express bus, which is commonly used at the edge nodes of industrial IoT systems. These SBCs support Gigabit Ethernet networks and can be connected to local peripherals such as printers via an onboard USB connection. The code storage area can be easily changed by replacing the SD card. It is worth noting that all computing devices, hardware and network protocols are the same as those used in factory automation.


Mobile router

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Figure 5: ADLINK's Express-HL COM Express board for industrial automation and railways. (Source: ADLINK)


Automated throttle, brake and gear control

The automatic operation of the locomotive's throttle, brake and selected gear ratio is based on accurate sensor measurements of the train and its surroundings. The sensor measures wind speed and direction, and calculates the effective force and direction of the train based on the weight, shape and inertia of the locomotive and the attached vehicle. The huge inertia of the train at that time was crucial for real-time control. The weather is also a factor, especially if it rains or snows. Consider the topology of the track, including whether the train is being upgraded, downhill or horizontal. All of this sensor data is sent to the locomotive's computer system to help determine the correct throttle and brake control.


Train horns and bells need to be audible in certain modes during certain train activities. For example, in the United States, a short sound is applied to the brake when the horn is standing. When the brake is ready to stop from the train in the upright station, the horn needs to make two long bursts of sound. When backing up, three short horns rang. Although all this was done manually by the operator in the past, in modern locomotives, it is now controlled by the computer of the train.


Inside the locomotive driving the train is a huge diesel engine. The GE Evolution series of locomotives use a large 12-cylinder diesel engine that produces up to 6,200 horsepower (4,620 kW). Industrial grade on-board computer systems automate the operation of the entire train in the same way as autopilots on airplanes. The throttle, brake and transmission are controlled based on sensor readings and compared to GPS data, planned routes, expected altitude changes, and the size and type of load. Efficiency is the key, everything is to provide the best fuel economy.


The basic formula for determining the train's acceleration torque and force is as follows:


Force/torque formula

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Formula 1: Calculate the acceleration torque and force of a large train


The key to these calculations is all sensor readings used to determine the large system inertia WK of the train. Although this is a single variable in the above formula, it is determined by considering hundreds of sensors on the train that are run by complex algorithms in the locomotive computer system. The automation of train throttles, brakes and transmissions can only be achieved if they are correctly calculated.


Of course, deceleration is also automated and is especially important in emergencies. If the train needs to decelerate due to an obstacle detected by the front camera imaging analysis, the front radar provides a close distance to the obstacle of the locomotive computer system. Calculate the speed of the entire train and the total system inertia at that time, and determine the deceleration torque and force. Based on the calculated optimal distance for stopping the train, the appropriate gear ratio and braking force are determined and the computer applies the brakes to stop the train. The computer will also repeatedly emit a horn as a warning. If the computer determines that the train cannot decelerate in time before it reaches the obstacle,


Wheel slip is one of the weakest links in locomotive operation. Excessive slippage in the drive wheels results in reduced efficiency, reduced fuel economy, and may compromise the safety of the train. While sliding in the past was only controlled by the driver's skill, the industrial IoT system in today's locomotives provides one of the most effective ways to minimize this important problem. The slip is measured by comparing the actual speed of the locomotive measured by the Doppler radar with the rotation of the drive wheel, which is proportional to the motor current. If the two do not match, the train's computer automatically adjusts the motor current to ensure maximum traction between the drive wheel and the track.


Maintenance and efficiency

The computer also controls the power flowing to the electrical components of the locomotive. This includes fans, battery chargers, blowers, lights and edge computers. This control is also attributed to sensors that sense temperature, speed and battery status. This level of control increases the reliability of the engine while making the locomotive more efficient. Predictive maintenance is another important feature of the Industrial Internet of Things. The wheel bearing temperature is measured and used to predict the end of life of the bearing. The shape of the wheel is measured by a sensor that predicts whether the wheel will become out of shape or even if it is not on the track.


It also measures the state of the entire train on the network. Each door, hatch and door are monitored or opened or closed, and in many cases the computer can be turned on and off automatically. Hundreds of sensors themselves self-diagnose to determine if they need to be replaced before a failure.


Each sensor reading, every action taken by the train, is recorded by the computer in a box, just like the "black box" on the plane. You can check these data later to find new ways to optimize train operation.


in conclusion

Modern diesel locomotives have come a long way compared to manual steam engines a hundred years ago. Each locomotive is its own industrial power plant with hundreds of sensors operating in exactly the same way as a fixed power plant. All of this automation increases efficiency, saves millions of gallons of fuel, increases safety, and extends the life of today's locomotives.