Edit post

Edit your reply below.

Post Body
Enter your post below.
[quote user="Overmod"]I'm not sure why a monocoque design would be necessary (or particularly appropriate) for the freight market in North America.  I'd expect either a revised version of CECX 1919 (for the Cummins QSK powerplant family) or something along the lines of the 'testbed' applications of parts of the Charger structure to hood units.  One of the main issues remains the desirability (or lack of same) in using excess DEF to permit the prime movers to operate at higher efficiency and still meet Tier 4 final and later standards. [/quote] A monocoque or in the case of the Charger a semi-monocoque design is chosen to save weight, about 20,000 lbs per unit but cost more to build. A standard freight locomotive is ballasted to the allowed axle loads. It doesn't make sense to save weight in the construction and add as ballast. We haven't seen any long time experiences with EGR in the GE ET44AC or EMD SD70ACe-T4 yet, so perhaps the railroads might perhaps reconcider. On the other hand EPA will release a Tier 5 sometime and it wiil require the use of SCR. In the final rule regarding the emission limits is discussed that locomotives would need SCR to comply to Tier 4. The manufacturers found a way around SCR. From that perspective I'm not sure if it was a wise decision in the long term to go for solely EGR  [quote user="Overmod"] And I don't see a reason why modern Siemens three-axle trucks couldn't be integrated under a monocoque structure, [/quote] As long as you get a semi-monocoque design within the axle load limits with two-axle trucks there is no need for three-axle trucks. The European experience is that two-axle trucks track better than three-axle trucks at higher speeds therefore the use of B-trucks. What I read about three-axle radial (steerable) trucks, the expierence is mixed so that in many cases the steering mechanism was disabled. Regards, Volker
Tags (Optional)
Tags are keywords that get attached to your post. They are used to categorize your submission and make it easier to search for. To add tags to your post type a tag into the box below and click the "Add Tag" button.
Add Tag