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Most LRV's are composed of multiple articulated sections. This allows a tighter turning radius. Each product line has a maximum number of sections, limited by its design. Common limits are 5 or 7 sections. Clearly very long LRV's require significant space at stops. The picture below clearly shows the articulations of a 3-section LRV.
Interior Layout and Passenger Capacity
All LRV vendors offer considerable flexibility and customization in the interior layout of the vehicles. The number, size, and location of doors are important considerations. Another key factor is the trade-off between seats and standing space, that can lead to very different passenger capacities. Assuming a ratio of 3 standing to 1 seated, a 7-section LRV may accommodate up to 300 passengers at a comfortable density of 4 passengers per square meter. It is also possible to pack up to 600 passengers at 8 passengers per square meter. The pictures below show some representative layouts.
All electric motors convert the energy of electromagnetic fields into rotating power. The history of electric motors in railroad traction has been a process of taking advantage of improving electronic technology. Newer systems use sophisticated electronic technology that has been made economical due to the high volumes of the communications and computer industries. In the early days, Direct Current (DC) motors were used because they were simpler to control. By the early 1980s, improved electronic technology allowed the use of Alternating Current (AC) AC motor in traction applications. These motors are simpler and lighter than DC motors.
Two AC motor technologies are used in current LRV's. The more established type for railway use is the asynchronous motor, also called an induction motor. The permanent magnet synchronous motor (PMSM) is gaining favor due to its wide use in hybrid automobiles. Asynchronous motors are simpler to control and inherently cheaper. PMSM's are lighter and smaller but they require more complicated controls. The additional cost of the permanent magnet is gradually easing because of the automobile usage volume.
Hybrid and electric automobiles have popularized the concept of "regenerative braking" where the kinetic (speed) energy of a moving vehicle is converted into electricity while braking. This done by turning the traction motors into electrical generators during braking. Most LRV's use this technology, but to take full advantage of it, an efficient and high capacity onboard energy storage mechanism is required. Battery energy storage is the most common technology being used in automobiles and LRV' for this purpose.
In fully electric cars battery charging is the only source of external energy during operation, but in LRV's the different running patterns and connection possibilities introduce a variety of power choices, and obviously the LRV high weight loads present a significant energy demand challenge. A common approach is to use a combination of overhead wiring and energy storage for segments where the wiring may be undesirable, such as historic settings. LRV operating ranges on stored energy of 1 to 5 miles (1600 to 8000 meters) are being claimed under limited conditions.
Both and nickel-metal hydride and lithium-ion batteries are being used in hybrid or electric automobiles and LRV's. Extensive research and development is being conducted on these technologies due to the volume potential in automobile use. Future selection will depend on the result of these efforts and the resulting cost differentials.
Another storage technology being used in LRV's is that of "super-capacitors." These are specialized versions of capacitor technology designed for transit applications. Compared to batteries, these components have a higher charge rate that can be used to store energy faster during the transit stops. This would facilitate having charging connections in only sections of the line. Their disadvantage is that they have a higher weight to energy capacity ratio than batteries. Cost differences will be greatly influenced by volumes in the future. Some new LRV's combine battery and capacitor technologies to include the benefits of their respective advantages.
This website is not a professional guide, but an editing of existing referenced material for educational purposes. The website author assumes no responsibility for any problems resulting from using the material presented in this website.
 Margarita Novales, Light Rail Systems Free of Overhead Wires, Transportation Research Record, Vol. 2219, pp 30-37.