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[quote user="Paul Milenkovic"]   <blockquote> <div><img src="/TRCCS/Themes/trc/images/icon-quote.gif" /> DwightBranch:</div> <div>   Don't take my word for it: http://www.csx.com/index.cfm/responsibility/environmental-leadership/ I think you are very wrong. Because of the much lower surface area of contact between wheel and rail (about the size of a dime) and far lower friction the mechanical energy required to move a similar weight on rails is much lower than for rubber tires on pavement. I used to watch switchmen push covered hopper cars around by hand in the ICG Bloomingon yards. I also drove a semi when I was a student, try to push that by hand, empty or not. <div style="clear:both;"></div>   </div> </blockquote>   I have studied the energy efficiency of rail and other modes of transportation since my days as an engineering undergraduate nearly 35 years ago when a professor of Mechanical Engineering at Northwestern University suggested I purchase a copy of Hoerner's Fluid Dynamic Drag, and my copy is either on the bedroom floor as we speak where I keep bedtime reading or in my home office under a stack of papers somewhere. The resistance of the steel wheel on steel rail is about a factor of ten lower than that of a pneumatic tire on concrete, but that is only at very low speeds.  At passenger trains speeds, there is considerable aerodynamic drag, which supplies the majority of the resistance for all modes -- auto, bus, train, airplane.  Furthermore, Hoerner reasons that there is a non-trivial aerodynamic drag in comparison to the rolling resistance from the rotation of train wheels and the wheels acting as centrifugal air pumps, but Hoerner also refers to a large anomoly in train resistance at higher speeds (anomoly being unaccounted increase) that he speculates is the coupling of linear motion into the side sway that is characteristic of trains and derived from the way cone-tapered wheel sets with solid axles are self-steering and exhibit kinematic "hunting." Trains should be favorable from the standpoint of aerodynamic drag because one train car is in the wind shadow of the train car ahead of it, and Hoerner devotes a great deal of page space to theoretical treatment of that effect along with the drag achieved in practice with the kinds of trains we have in operation.  Railroads, especially in the U.S., have long been skeptical of streamlining as the shrouds and covers increases maintenance expenses by making it harder to access various parts, and maintenance has long been a much larger expense in railroading until the runups in fuel prices starting in the mid 1970's.  2nd-gen Shinkansen, TGV, and ICE trains are light weight and carefully streamlined as a result of wind tunnel tests, and some of the very favorable energy efficiency CO2 emissions reported for these trains may result from these optimized designs, even when operated at high speeds.  How that streamlining impacts the maintenance costs is not known, but maybe that is a maintenance man-hour vs fuel cost trade that pushes you in the direction of finely tuned streamlining for HSR and aviation. If you have looked at the underbody clutter of an Amfleet coach, U.S. passenger cars are streamlined not nearly as much, and Hoerner goes into great detail in interference drag effects and how the detailing of a train, auto, or airplane can result in much higher drag than the theoretical minimum. The other consideration with passenger rail is that passenger trains are much heavier on a per seat basis than any other mode of transportation.  That weight incurs losses in accelerating the train to speed or when climbing even modest hills, and even an electric train using regeneration recovers only a portion of that weight-induced energy consumption.  U.S. passenger trains, furthermore, are perhaps twice as heavy as anything in Europe or Japan on account of the FRA safety standards.  Those standards may be waived for a completely dedicated HSR line with positive train control, although it is hard to see those standards ever being waived for anything that interacts with freight with the train lengths and loadings in the U.S..  Who wants to be the person waiving that seeming unnecessary requirment and then a grisly accident takes place? The other cultural aspect to trains is that there is an expectation, especially in the advocacy community, regarding trains being a particularly comfortable and spacious accomodation, where one is free to leave one's seat and walk around, perhaps walk to a dining car or the entire Talgo car dedicated as a "bistro car" on the 86-mile Chicago-Milwaukee train, if the Talgo is ever put in service there owing to the political in-fighting in Wisconsin. The one and only time I was ever on HSR was in Japan in the late 1980's, and I rode in one direction in the unreserved coach, which was 5-across seating, not as crammed in as a regional jet, but comparable in elbow room and seat pitch to the last time I rode a DC-9 jet, which was a year ago. Maybe all of that "walking around room" and train cars devoted to dining and other amenities is a requirement of non-HSR trains given the culture of what is expected of train travel in the U.S., and maybe if we had HSR with airline trip times, we would go to 5-across seats as they do in Japan?  Would 5-across seats in a 1 Hr 35 Min Hiawatha train trip from Chicago to Milwaukee be a reasonable way to accomodate the burgeoning ridership, or would the advocacy community raise strenuous objections?  If we had HSR, would the advocacy community object to going to much higher seating density as they do in Japan in trade for the much shorter trip times? The other thing you need to factor in is load factor, how many seats are occupied.  Airlines get their seemingly favorable energy efficiency these days by packing people in, both with short amounts off leg room and running planes nearly full all the time, which imposes all manners of inconvenience with regard to travelling at the times you want to.  The France TGV has airline-level load factors, but I do not have any personal experience on how hard it is to book a TGV ride on the day and time you want and whether the nearly-full TGV train is similar in experience to riding a nearly full jet.  David Lawyer (the guy who has looked into transportation energy efficiency in real-world data I linked to) suggests that trains run at percent-seats-occupied levels not that different than automobiles.  Do we really want to run trains as full as airplanes, with the inconvenience of planning your trip on when the airline has cheap seats and the Greyhound-Bus aspect to modern airline travel of being stuffed into a tube in close quarters with people you don't know? With respect to your link to CSX discussing the energy efficiency of trains, trains are a particularly energy efficient way of moving things that are dense and heavy at low speed, i.e. freight and especially bulk freight.  To the extent that trains need to be heavy to be safe (and also because of the shock and vibration aspects of steel-on-steel contact -- efforts at light weight trains such as Talgo and the United Aircraft Turbo Train have frequently been criticized by commenters on this forum as sacrificing ride quality), to the extent that there is a cultural expectation that we give passengers lots of personal space in a high-weight conveyance to begin with, and to the extent that streamlining works against doing maintenance operations on trains in a cost-effective manner, passenger trains may not effectively utilize the low-rolling resistance property of the steel wheel on steel rail mode. I could check out the "carbon calculator" linked on your other post.  I had checked out the carbon calculator of the California HSR Authority and commented at length on another thread that in my engineering judgement, the numbers were overly optimistic.  In my opinion, the carbon calculator made unrealistic carbon consumption assumptions regarding automobiles, since by the time the CHSR is operational, cars will have made substantial strides in fuel efficiency owing to President Obama's rule making on more stringent CAFE standards. As to argument-by-authority, I have been participating in passenger train advocacy since the late 1960's, and I have been making calculations and looking at data on transportation fuel efficiency since the mid 1970's because the energy efficiency aspects to transportation is one topic I am truly passionate about.  If someone has some hard data on this topic, I am really interested in seeing it.  Another thread suggested that Amtrak Diesels all have digital readouts visible from platform-side of their fuel levels, and it should not be to hard to ride the Hiawatha or Pacific Surfliner and get those readouts upon embarking and disembarking the train?  Are there Amtrak conductors on this forum who could get this info -- I would like to know Station A, Station B, the fuel burn, the time and date, and the consist. To anyone who is new around here, we have a research engineer with over 30-years experience, an accountant from the electric-power utility industry with an even longer work history along with international experience, and an employee of a major U.S. railroad lurking around this forum, all of whom are railroad enthusiasts and passenger-train advocates in their own way, and any assertions about passenger trains will be subject to much more intense scrutiny than your local circle of passenger-train advocate friends. [/quote] Another thoughtful and thorough explanation from Mr. Milenkovic.  He is as mindful of the opinions from the guys and gals who work the trains as a fellow professional engineer.
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