**5.4 Dual power hybrid locomotives**

A **hybrid train** is a locomotive, railcar, or train which uses an onboard rechargeable energy storage system (RESS), placed between the power source (often a diesel engine) and the traction transmission system connected to the wheels. An example is the hybrid locomotive ALP-45DP with dual drive developed by Bombardier. It is designed as a diesel and electric locomotive. The hybrid locomotive can reach a speed of 160 km/h under diesel drive and up to 200 km/h under electric drive. For a higher efficiency, it can be switched from the diesel drive to the purely electrical operation with just a button push [34].

### **5.5 Efficient and ultraclean diesel-electric locomotives and repower kits**

General Electric (GE) Evolution Series is a diesel-electric locomotive with 12-cylinder engine. It is currently considered the most fuel-efficient and technologically advanced. This product is viewed to be particularly environmentally friendly and

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*Energy Efficiency Management: State of the Art and Improvement Potential Analysis…*

railways, which are constantly confronted with rising fuel costs [34].

network with the LEADER train management and control system [34].

**5.7 Alternative fuels for environmental sustainability**

*5.7.1 Hydrogen fuel for fuel cell hybrid locomotives*

hydrogen fuel cell [34].

cell stack with 240 kW

• Corresponding power electronics

• Battery ventilation systems

**5.6 Distributed power management and control technologies for freight rail**

Unlike the traditional push-pull configuration, decentralized power supplies place locomotives in the middle and at the ends of the trains. Distributing the locomotive power along the train can achieve about 5% more energy efficiency (compared to the push-pull configuration). This is increasingly being used by freight trains. Due to the power distribution, there is an increase in safety, as the trains are less susceptible to derailment [36]. The wear of wheels and tracks as well as the braking distance can be significantly shortened by the distributed power. To achieve a desired speed curve, distributed energy control and power management software is used. Various companies such as Canac and Wabtec offer solutions for the decentralized electricity market. Norfolk Southern saved nearly 30% on fuel with a combination of electronically controlled pneumatic (ECP) brakes that communicate with GE's Locotrol over the

Hydrogen has been considered for use in rail transportation [37, 38]. Alternative fuels for locomotives are particularly important for environmental improvement in the rail sector. With the use of hydrogen fuel cells, a reduction of particulate matter pollution and greenhouse gases emitted into the atmosphere can be achieved. The dependence of the iron webs on fossil fuels is reduced to a minimum with the

• Batteries for driving electric traction motors, which are charged by a Ballard fuel

The batteries that drive the electric motor are charged by the fuel cell. To ensure

sufficient traction between rails and wheels, the locomotive carries 900 kg of

In the hydrogen hybrid locomotive, the following components are used:

• Hydrogen tanks storing 70 kg of hydrogen at 350 bar on the roof

currently has about 3700 locomotives in 10 different countries in use [34]. It has the advantage over other clean locomotives that no urea additive for selective catalytic reduction (SCR) is needed to reduce NOx emissions. There are no expensive infrastructure upgrades to store and deliver urea for denitrification. New locomotives are very expensive to buy, so a cost-effective option to achieve energy efficiency would be to retrofit existing locomotives with repower kits that reduce fuel consumption and emissions. Progress Rail Service (PRS) acquired in 2010 is a Caterpillar division, Electro-Motive Diesel (EMD), which has long been producing locomotives. The goal of the acquisition was to switch low-power, regional, and high-performance longrange mid-power locomotives to cleaner operation through repowering and achieving more efficient traction. The 710ECO Repower locomotives significantly reduce fuel consumption. Up to 25% of fuel and even 50% of lubricating oil can be saved. This is highlighted by the manufacturer as one of the most important advantages for

*DOI: http://dx.doi.org/10.5772/intechopen.86552*

*Energy Efficiency Management: State of the Art and Improvement Potential Analysis… DOI: http://dx.doi.org/10.5772/intechopen.86552*

currently has about 3700 locomotives in 10 different countries in use [34]. It has the advantage over other clean locomotives that no urea additive for selective catalytic reduction (SCR) is needed to reduce NOx emissions. There are no expensive infrastructure upgrades to store and deliver urea for denitrification. New locomotives are very expensive to buy, so a cost-effective option to achieve energy efficiency would be to retrofit existing locomotives with repower kits that reduce fuel consumption and emissions. Progress Rail Service (PRS) acquired in 2010 is a Caterpillar division, Electro-Motive Diesel (EMD), which has long been producing locomotives. The goal of the acquisition was to switch low-power, regional, and high-performance longrange mid-power locomotives to cleaner operation through repowering and achieving more efficient traction. The 710ECO Repower locomotives significantly reduce fuel consumption. Up to 25% of fuel and even 50% of lubricating oil can be saved. This is highlighted by the manufacturer as one of the most important advantages for railways, which are constantly confronted with rising fuel costs [34].

### **5.6 Distributed power management and control technologies for freight rail**

Unlike the traditional push-pull configuration, decentralized power supplies place locomotives in the middle and at the ends of the trains. Distributing the locomotive power along the train can achieve about 5% more energy efficiency (compared to the push-pull configuration). This is increasingly being used by freight trains. Due to the power distribution, there is an increase in safety, as the trains are less susceptible to derailment [36]. The wear of wheels and tracks as well as the braking distance can be significantly shortened by the distributed power. To achieve a desired speed curve, distributed energy control and power management software is used. Various companies such as Canac and Wabtec offer solutions for the decentralized electricity market. Norfolk Southern saved nearly 30% on fuel with a combination of electronically controlled pneumatic (ECP) brakes that communicate with GE's Locotrol over the network with the LEADER train management and control system [34].

#### **5.7 Alternative fuels for environmental sustainability**

### *5.7.1 Hydrogen fuel for fuel cell hybrid locomotives*

Hydrogen has been considered for use in rail transportation [37, 38]. Alternative fuels for locomotives are particularly important for environmental improvement in the rail sector. With the use of hydrogen fuel cells, a reduction of particulate matter pollution and greenhouse gases emitted into the atmosphere can be achieved. The dependence of the iron webs on fossil fuels is reduced to a minimum with the hydrogen fuel cell [34].

In the hydrogen hybrid locomotive, the following components are used:


The batteries that drive the electric motor are charged by the fuel cell. To ensure sufficient traction between rails and wheels, the locomotive carries 900 kg of

*Transportation Systems Analysis and Assessment*

**5.2 Energy efficiency for high-speed rail**

of energy efficiency [34].

to frictional heat and is thus lost. The recovered braking energy can be redirected back into the system or used for peak load requirements such as accelerating or uphill driving. Modern or newer electric train systems are able to save and reuse 10–20% of energy consumption with the aid of the regenerative braking function. For rail freight traffic with numerous stops, this is particularly interesting in terms

Freight railways deserve a lot of attention as they require about 90% of the energy of domestic rail transport. In 2011, the American Public Transportation Association (APTA) cited some UIC data in a report stating that the high-speed trains achieved about 106 mi (170 km) per kWh of energy. In comparison, planes only get 13 mi (21 km) and cars 34 mi (55 km) per kWh [35]. High-speed rails (HSR) and maglev (magnetic levitation) systems have many advantages over conventional rail, highway, and air, especially in terms of air quality and sustainability. CO2 emissions from HSR operations are significantly lower (0.1–0.3 lb of CO2/passengermile or 0.03–0.08 kg/passenger-km) than other modes of transport such as aircraft (0.6 lb./p-mi or 0.17 kg/pkm) or cars (0.5 lb/p-mi or 0.14 kg/pkm). An up-to-date life cycle analysis of HSR versus traditional rail, air, and highway modes found that system-wide comparisons of rail infrastructure construction and operation, high load and occupancy factors, maintenance and fuel, and clean electricity must be supplied with renewable energies (instead of, e.g., coal-fired power stations) [34].

**5.3 Diesel multiple units (DMUs) and electric multiple units (EMUs)**

friendly and more energy-efficient and can achieve higher speeds [34].

**5.5 Efficient and ultraclean diesel-electric locomotives and repower kits**

**5.4 Dual power hybrid locomotives**

operation with just a button push [34].

Self-propelled diesel railcars can be diesel-electric, diesel-hydraulic, or dieselmechanical units. These traction vehicles (including powered wheels) can accelerate much faster and have a shorter braking distance than locomotive trains and are thus also more energy-efficient than these. As long as the powered vehicles are connected by cable or radio link, they can be used in the decentralized power configuration. Another form of self-propelled railcars are electric multiple units (EMUs). EMUs are individually powered by direct current (DC) from a third rail, but there is also the option of being powered by a vehicle pantograph in contact with the AC overhead line system (OCS). EMUs are more costly than DMUs but are more environmentally

A **hybrid train** is a locomotive, railcar, or train which uses an onboard rechargeable energy storage system (RESS), placed between the power source (often a diesel engine) and the traction transmission system connected to the wheels. An example is the hybrid locomotive ALP-45DP with dual drive developed by Bombardier. It is designed as a diesel and electric locomotive. The hybrid locomotive can reach a speed of 160 km/h under diesel drive and up to 200 km/h under electric drive. For a higher efficiency, it can be switched from the diesel drive to the purely electrical

General Electric (GE) Evolution Series is a diesel-electric locomotive with 12-cylinder engine. It is currently considered the most fuel-efficient and technologically advanced. This product is viewed to be particularly environmentally friendly and

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ballast. In the case that the temperatures of the batteries are too high, a pressure relief device can be activated. This process ventilates the batteries as well as the hydrogen fuel cells. With this model, the air pollution and the noise pollution at the stations are reduced. The problem with this variant is the limited range between the fueling and the hydrogen storage capacity [34].

#### *5.7.2 Natural gas locomotives using liquefied natural gas (LNG)*

Liquefied natural gas (LNG) is an interesting alternative fuel for locomotives [39, 40]. Westport Innovations is working with Caterpillar to develop a natural gas fuel system for locomotives [34]. This project uses high-pressure direct injection technologies for combustion. The main objective was defined as the production of emission compliant long-haul locomotives with interchangeable tender vehicles. With this technology, 95% of the diesel fuel is replaced by natural gas and thus only 5% diesel fuel used for combustion to bring the locomotive to full capacity. Energy Conversions Inc. is working with Burlington Northern Santa Fe (BNSF) to develop a convertible engine with a dual-fuel system. This system uses low-pressure direct injection (LPDI) with no pump being required. The NOx emissions caused by premixed combustion are reduced. This system can save up to 1.1 million liters of diesel per year per locomotive, equivalent to a possible replacement of 92% [34]. According to BNSF, the economy and technology have been improved so much that natural gas in long-haul locomotives becomes operationally feasible [34].

#### *5.7.3 Biofuels and blends with petrodiesel*

Biofuels are derived from renewable and (in principle) non-exhaustive sources of energy. To produce biofuels, biological (plant or animal) materials are converted into liquid fuel composed of fatty acid methyl esters (FAME). Instead of fossil fuels, organic waste (e.g., waste cooking oil) can also be used for production [41, 42]. Biodiesel fuel is obtained from transesterification of fatty acids. In this chemical process, glycerol is separated from fat or vegetable oil, and methanol is consumed. Biodiesel is made from a variety of products, such as animal fat, vegetable oil (rape seed, soy bean, palm oil, etc.), or recycled restaurant fat. Petroleum diesel can be blended with biodiesel to any percentage. In these biodiesel blends, the percentage of biodiesel is always clearly marked. For example, B10 contains 10% of biodiesel, with the remaining 90% being made from fossil sources. Pure biodiesel is known as B100. Blends containing more than 20% biodiesel require special handling or even modifications of the equipment. Biodiesel is biodegradable and nontoxic, reduces air pollutants, and provides better lubricity due to its viscosity. The high cetane number facilitates combustion in compression ignition engines [34].

For two recent reviews on biodiesel, see [43–45] for biodiesel in railway use. Bioethanol is more a fuel of choice for smaller (gasoline) engines.

Other biofuels are, e.g., biobutanol and biomethanol [3, 46].
