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20/25kV EH800 locomotive testing and revenue freight


bikkuri bahn

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The main difference is the support of 25kV AC for the Seikan tunnel. The EH500 could only use 20kV AC, which means it can not be run together with shinkansens. Other parameters (like maximal power) seems to be the same. It's funny that the japanese freight locomotive design returned to the double chassis 4 bogies EH10 style after so many locomotives with 3 bogies.

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I wonder why that is actually, is there any advantage of a such a 'twin locomotive' over a normal 2/3-bogie loco?

Edited by Densha
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I wonder why that is actually, is there any advantage of a such a 'twin locomotive' over a normal 2/3-bogie loco?

The advantage over a 2/3 bogie loco is the larger number of wheels, so a larger adhesion surface which allows a larger starting power and puts less wear on the tracks. Also, the power of each traction motor could be lower. Another advantage over a 3 bogie loco is the more equal weight distribution on the bogies on uneven terrain and the much simplier mechanical structure. The 3 bogies with 2 axles locomotive design was choosen over the 2 bogies with 6 axles design because it can negotiate sharper curves on cape gauge with less stress on the tracks. The downside is that since the main frame is rigid, on a hilly terrain, 2 bogies are always loaded more than the 3rd. The swiss/italian solution for this was to split the main frame and create articulated locomotives. The us/russian solution was to make multiple unit locomotives, usually twin or 3 section ones. The japanese first used the 3 (or 3+1/3+2) axle design, then the bo-bo+bo-bo design in the EH10, then switched to simple bo-bo designs used in multiple units, added a middle wheel (bo-1-bo), middle bogie (bo-2-bo) for weight reasons, then added power to the middle bogie (bo-bo-bo) and after a few years, they realised that by building simple bo-bo locomotives and making twin units out of them with some of the equipment split is much simpler, cheaper and more effective, so they returned to the design of the EH10. As far as i see this works for now. Another example is the super rail cargo unit, where they use 2 twin locomotives with split equipment and multiple unit two of these, creating a bo-bo+bo-bo ... bo-bo+bo-bo design.

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