Starting with http://cta.ornl.gov/data/tedb26/Spreadsheets/Table9_10.xls, Amtrak’s most recently-reported energy use is 2700 BTU/passenger mile, down from a high of 3200 in 2000 and up from a low of 2400 in 1991. Using a figure of 125,000 BTU in a gallon of gasoline (the high heating value) and 140,000 BTU in a gallon of #2 Diesel, this works out to 46 passenger-miles/gallon gasoline (MPG will be gasoline unless indicated). Their averages work out to 20 persons per train car. A train car averages 2.6 Diesel MPG, contrasted with a figure of 6 Diesel MPG stated for intercity buses.
To put these numbers in perspective, I looked into some train resistance calculations - the Davis formula had been suggested on another thread. My source for train resistance is S. F. Hoerner, 1965, Fluid-Dynamic Drag Dr. Hoerner was a German aerodynamicist who emigrated to the US after WW-II. The book was recommended to me by a Mechanical Engineering professor at Northwestern University when I had asked about drag numbers for determining the fuel economy of trains. The book is self-published by the author, and I had ordered a copy from his widow at Hoerner Fluid Dynamics, PO Box 342, Brick Town, NJ 08723, but that was over 30 years ago. But the laws of physics haven’t changed. Page 12-15 gives a chart for rolling resistance (Davis formula) and aero drag for a 400 ton train with “conventional” aerodynamics and with streamlining.
My baseline train is the Amtrak Hiawatha Service, currently operating a 5-car train with a P42 at one end and an NPCC (non-powered controlled cab) F40 at the other end. The weight of this train is 525 tons – 125 tons at each end and 55 tons each times 5 cars. I am assuming the upper end of Dr Hoerner’s drag numbers for this train, owing to the unstreamlined underbodies of the Horizon cars and the step mismatch between these lower prof
This points out the effect of the extra 132 tons being hauled around on the Hiawathas.
My concerns are whether there is room for a fast 300-passenger train in the rush hours, how to best accommodate the demand for longer-distance travel, and what is the cost of additional capacity for limited periods?
Another issue is the practice of focusing on maximizing revenue per passenger rather than increasing overall revenue and ridership more than cost. The trains then can become a social tool to reduce less efficient driving, highway congestion, energy consumption, emissions, and consumer cost.
You may be interested in an article, “Optimizing Aerodynamics to Raise IC Performance” by Jean-Luc Peters in the Oct, 1982 Railway Gazette International. I was able to translate this into the Davis formula and program calculations using Basic. Unfortunateley, Basic is obsolete and current programming languages are beyond this old dog.
I am getting the impression that you are comparing apples to oranges here. How exactly did you arive at the 6 MPG figure for intercity busses? Since you cite no details on this figure the rest of the information in your post is useless.
A better way to compare the fuel efficieny of busses to trains would be to compare the MPG per passenger seat rather than the average number of passengers carried. By this method you can compare the potential energy savings of one mode over the other on equal footing.
However I must also note that there is more to energy efficiency than just MPG. To be fair you must also compare the energy consumption of the infrastructure that supports the two modes of transport. Wich consumes more energy to build and maintain, a mile of interstate freeway or a mile of 79 MPH mainline track? You simply leave this part out of your equations.
When you come up with appropriate facts and figures Paul you will see that trains are the most energy efficient means of land transportation.
That is an interesting point that the energy-intensity of the guideway/roadway should be taken into account in comparing the energy intensity of transportation modes. I don’t have any data on that but would welcome any input or comparisons on this issue. One should also add the energy required to manufacture the rolling stock – cars, buses, trains. On the other hand, when the energy use of different modes of transportation is discussed in many forums, the fuel consumed by the vehicle is what is often reported.
As to the “apples and oranges” and the matter of a “fair” comparison between buses and trains, a large part of the improved fuel efficiency of buses is that they operate at higher seating densities, with the seats practically crammed together, and they operate at higher load factors, more people packed into those seats. On the load factor issue, bus operators will dispatch more buses during peak travel times; Amtrak, however, is running fixed consists on its corridor trains.
There is also an expectation in the advocacy community that trains provide a greater level of comfort through much lower seating densities along with amenities provided by non-revenue cars on long-distance trains. The lower seating densities, the low overall load factors required so as to not turn people away at peak times, and the expected levels of amenities on trains are a tradeoff against fuel efficiency. If the reason for promoting train travel is to save energy, for reasons of reducing oil imports, greenhouse gas emissions, and so forth, the advocacy community may have to accept reduced levels of such amenities on trains.
There is a widely-held assumption that not only are
I looked at Lawyer’s website and while I would quibble about the relative efficiencies of cars and locomotives, he does get it right in that LD trains weigh A LOT per passenger. Interestingly, that is something that John White brought up in the mid-1970’s in his book The American Railroad Passenger Car. I’d also argue that an electrified line offers the advantage of a much more diversified energy supply, but the only LD electric line is the Northeast Corridor.
Kind of a shame when remembering that both the M-1000 and the Pioneer Zephyr could hit 110 MPH with a 600HP engine and the M-1000 was originally designed to use engine heat for heating the train.
Commuter rail is a different story in that the GO Transit design weighs less than a 1,000 pounds per seat. A further improvement could be made by using hybrid locomotives to store braking energy, though batteries don’t yet have the cycle life and ultracaps don’t have the specific energy needed to make a practical hybrid commuter locomotive.
Here we go again. I think my favorite argument of yours has been “that SUV with 3 of your buddies riding is more efficient than Amtrak”. Of course it’s convenient to forget that 90% of the time that SUV has one occupant commuting to work. Once you buy the car, you use it all the time, not just when it can be used at max efficiency. You have to. Cars cost a lot to keep. It’s also easy to forget that those four guys in the SUV after the ball game were probably at creep speed for several hours in the obligatory traffic jam. So much for efficiency.
I see some of that here, too. You’ve calculated an overall “fuel mileage per car” for Amtrak based on their reported energy use. Well and good. But then you compare that unfavorably to the 6 mpg a bus gets. Full service brakes! You’re not using an overall energy consumption value, but a value that disregards time spent in heavy traffic, time spent idling and going nowhere, and other periods when the bus can’t get highway mileage. Your Amtrak calculations include all of these! How is that comparison at all valid? Also - time stopped at signals waiting for freights. And I would love to see how that varies from RR to RR!
Listen, engineer. (and it’s ok for me to say it, I’m one too) We like to forget it, but you can’t just look at the vehicle. You have to look at the system. My car can get 30 mpg easily, but in practice I get around 18 mpg. Lots of time stopped at lights, going in slow traffic, etc. And I don’t even live in a very large city.
I forget what the average number of people per car is…around 1.2, I think, but that’s probably high. Using a real-world fuel mileage of about 24 mpg for a practical-sized car like a Taurus or Accord, that gives you around 29 pax-mile per gallon, assuming you aren’t stuck on the Jersey Turnpike, in which case all bets are off. The real-world Amtrak car you mentioned, assuming your figures are good, gets 52 pax-mile per gallon.
I suppose so. It was late and maybe I should have used more sand toward the end there…slipped a little. It’s kind of hard to say the car did it, though, because at the same time the country was being rebuilt in a way that made the car necessary, and one part of that was the bustitution of transit systems. But that’s another ugly mess for another day.
Anecdotally, you and I know that people don’t like city buses. I ride city buses, and I have to say I see their point. Noisy and shaky, for one thing. If the bus line was treated as a show horse, not a pariah…but again, that’s for another day.
My major point still stands. As utilized now, /according to the figures given by PM/, Amtrak gives tiny-hybrid-car level fuel economy, but with comfortable seating, bedrooms and a restaurant on board, the capability to safely go upwards of 80mph, and a traffic management system that keeps traffic jams uncommon, not a daily reality. And potentially, with very few changes and no sacrifice in comfort, we could improve the efficiency, go 100mph, maybe 120, and use that system to keep the trains moving on time.
My limited recent experience with Amtrak is that the trains, both long-distance and Midwest Corridor, have been pretty full and need to be given a break regarding energy consumption that is related to train weight.
The Builder and Southwest were nearly full across Montana and Colorado in late September and mid-May respectively.
The 7:00am from Chicago to Saint Louis and Springfield may have been half full; but the returning trains were on average three-quarters full in the middle of the week with three coaches and a buffet-business class car.
The Chicago - Saint Louis trains are turned; but the Hiawathas have the “cabbage” car ballasted to 263,000 lbs without the engine. This adds the equivalent of two more coaches in train resistance and consumes more fuel.
A 10-car, 2-locomotive superliner train with 300 passengers works out to roughly 7,700 lbs per passenger, about three times the weight of a compact auto. Then too, it’s travelling with the motel and restaurant while an auto, bus, and plane travel between fixed facilities. I am not advocating meal stops or over-nighting. On-board facilities make up for running slower on a 19th Century alignment than flying and, in many cases, driving on 20th Century expressways.
If the “average” corridor train averages 20 passengers per car, the weight for a 4-car train works out to around 10,000 lbs per passenger! This is four times the weight of a compact. Rush hour Hiawatha #330 with 270 passengers and “cabbage” car weighs 4,100 lbs per passenger. Another coach was added and the train still may be full. If Amtrak achieves forty-six passenger-miles per gal, a full train such as the Hiawatha would achieve over 150 pm/gal and beat a Prius three times over.
I still think pricing is the key; and Amtrak is focused on revenue per passenger more than train revenue. Could the average ridership double if train tickets were hal
Of course the train in nearly full the times you are on it. Andecdotal reports of load factor have a known observation bias. The times that the train is nearly empty are the times you are not on it because no one else is riding it either.
Some people look at a train with 50 percent load factor and see a train half full. Others look and see a train half empty. I look at such a train and see a transportation service that is flexible enough to accomodate peak demand.
Part of the reason flying is so uncomfortable is that not only are the seats packed close together, it seems everytime one is on one of those things, it is nearly full, with people who take on too much carry-on luggage and hog the arm rest and the whole experience of being crowded together with strangers. Aviation achieves the fuel economy that they do because the run such high load factors, using the trick of selling a seat in the same cabin for widely different prices depending on that passenger’s willingness to pay. Ever notice that when you book airline seats it is like haggling at the souk? Oh, I could get you out Tuesday at 1 PM, but that flight is $600, but if you were willing to take the Tuesday 6:45 AM flight, the fare would be only $450.
The airlines get away with this because a cheap seat is more important to people than the convenience of not having to get up at 4 AM to make the 6:45 AM flight. We put up with a lot from the airlines because for a lot of the distances we are trying to cross, the airplane is much faster than any surface alternative, even with taking the airplane on the airline’s preferred time and the TSA lines and so on.
The train I numbers I crunched for the Hiawatha were for the ridership numbers that are tout
Whether anecdotal experience creates an impression or illusion, it raises doubts about the veracity of presentations to the contrary.
My emphasis was on filling the existing seats, not adding a couple more rows to improve fuel efficiency without adding another car. That alternative didn’t come to mind. Given tight equipment supply, maybe it’s better to have seats to sell than turn people away and get better mileage to boot.
Is my veracity being questioned here? It is simple math. Pick whatever number you believe represents the passenger boardings on the Hiawatha. I rounded the number to 500,000 – it has been lower in prior years, ridership has been up lately. People pretty much ride this thing end-to-end, so riders divided by seats equals load factor. There are 7 trains a day in each direction except for Sunday when there are 6. 98 trains/week times 52 weeks in a year is 4992 one-way train trips/year. 500,000 divided by 4992 is 100.16, which I rounded to 100. On average, throughout the year, about 100 passengers ride the Hiawatha train.
You have a different set of numbers, different conclusions on the energy efficiency of these trains, tell me what they are.
To give you an analogy of where being a believer in something gets you, consider Feynman’s critique of the Space Shuttle. He wanted someone to tell him their best engineering estimate of the rate at which they could expect to have an accident with one of those things. He talk to sources who estimated the accident rate to be 1 in 25 launches; he talked to some NASA engineers who believed it to be 1 in 100. Those numbers are not picked out of the air – there are many more non-Shuttle rocket launches, and those figures are optimistic for those other rockets. He talked to the Shuttle managers, who believed the accident rate to be 1 in a bajillion, and they would not even allow themselves to be pinned down on roughly how much a bajillion was.
The actual accident rate has been somewhere in the range between the 1 in 25 and the 1 in 100 – nowhere near the 1 in a bajillion.
Same thing here. When I crunched the numbers to come up with an engineering best-guess as to the fuel economy of the
Your veracity is not being question; it’s the numbers that conflict with my unscientific experience that nevertheless raises doubts. Furthermore, this related to the discussion regarding long-distance trains, specifically the Builder and Southwest.
I saw recent Hiawatha monthly ridership and, indeed, the averager number of passengers per train is about 100. I’ve seen enough Hiawathas go by to know that 100 passengers on average can’t be far off the mark. Trains 330 & 339 may carry three times the average; but that becomes an even harsher criticism of the service.
A monthly ticket between Chicago and Milwaukee costs $321, the equivalent of $7.30 for 44 trips a month. I wonder how many people would ride the Hiawathas if the one-way fare was reduced from $21 to $12? Or to $14?
On the load factor question, I am not by any means taking the position, “Oh, the load factor is low, no one is riding Amtrak.” The load factor is just one variable in the operation of a transportation system.
For example, a given highway may be jammed up at rush hour, but there may be only two cars on the road at 3 AM. We don’t say, “Oh, this highway is underutilized because no one is taking it at 3 AM.” Also, when people form an opinion as to the capacity of the highway, they naturally base it on the jammed-up rush hour experience rather than the 3 AM experience. One difference is that a highway just sits there and doesn’t require fuel to put into motion; to provide a similar capacity to be available when people decide to use it, you need to put train cars in motion.
As to the idea of lowering the fare to increase utilization of the train, the Hiawatha train is already at capacity, at least at peak times as evidenced by the initiative to add a train car to the consist. To increase the load factor, one would have to play the airline game of offering lower fares for off peak runs, raising the fare and perhaps turning people away for peak times. Aviation is intrinsically an energy-intensive mode, and the airlines have achieved “reasonable” passenger MPGs by cramming in seats and aggressively filling those seats.
Railroading is intrinsically much less energy-intensive, allowing railroad operations to offer more space, operate at lower load factors for the convenience of passengers, and provide amenities on the long-distance runs. The passenger train has a much larger weight budget of pounds per seat or pounds per passenger to achieve roughly comparable fuel economy as aviation. The concept I have trouble getting any consensus on is that passenger trains start out with a much larger weight budget, but that larger budget can be quickly spent on all of those things that people regard as intrinsic to tr
I beg to differ that fuel consumption for building and maintaining hiways is a one off event. Anyone who has driven on the Interstate hiway system can atest to the massive perpetual maintenance and expansion projects that are needed to keep the freeways functional. In addition you must consider snow removal, salting, and sanding of all roads durring the winter months.
Plus you must factor in the massive amount of freeway infrastructure that is “functionally obsolete” that is in dire need of replacement (remember that big bridge colapse in the Twin Cities?).
On a final note Samantha I want to make a comment on something you wrote about in another post, that of so called “Intelligent Highway Systems” or IHS for short. As I recall you stated that the future of American transportation will rely on cars that can drive themselves using sophisticated onboard auto pilot computers linked with guidway computers imbeded in the streets.
Even on its own terms this scheme is ridiculous! Never mind the cost of installing all of this computer hardware in our Interstate System and the vast motor fleet and then the debuging and maintenance that this system will need. One has to wonder: What is to stop people from driving unequiped vehicles on these automated systems; after all many people operate vehicles without proper licenses and insurance but that doesn’t stop them from getting out on the road.
As James Howard Kunstler, author of The Long Emergency wrote “Proposals such as IHS demonstrate how overinvestment in technological complexity can continue far beyond the appearance of obvious diminishing returns.” (p. 266)
You asked whether persons in cars without guidance equipment would violate the Intelligent Highway System by entering the roadway. Actually, this might be controlled at entrance ramps with open tolling technology and barriers.
The more fundamental question is whether IHS poses de facto economic discrimination. The highway industry has perpetuated the myth that public roads are for everyone, overlooking the facts that segments of the population cannot drive and others not as competent as may be desired must be accommodated, and justifies general pulic support in taxation. A person who can barely afford a junker, licensing, and insurance cannot afford the considerable cost of the telemetry, guidance, and speed control systems required for IHS driving. IHS will be particularly burdensome for people inversely proportional to incomes.
I second your comments regarding highway costs and energy consumption not ending with the initial construction. However, you missed the costs of policing, emergency road services, sweeping and trash removal, and mowing and gardening.
I said, “The amount of energy used in building a highway or railway line, when depreciation over the life of the project is considered, is probably marginal compared to the energy used in operations.” I did not say anything about maintenance.
It is true that energy is used to maintain a highway, or any infrastructure for that matter, including a railway line. I have not researched the per passenger mile maintenance costs for the airlines (planes, airports, air navigation systems) and the railways nor the vehicle miles traveled for the highways. Whether there is a significant difference in the unit cost, which would include energy, is problematic.
A high speed railway line, such as Amtrak’s NEC, is maintenance intensive. I would be surprised if the maintenance cost per passenger mile on the NEC is significantly lower than the per passenger mile charge for the airlines or vehicle mile traveled for the highways. This would include the capitalized energy, which again would be a one off for the maintenance project, unless it is continuous maintenance such as snow removal. In any case, it is probably a minor percentage of the energy consumed by the operating vehicles over the initial or extended life of the asset.
I believe that I said electronic guidance systems for selected highways are a possibility. GM has tested the concept. Of course, it is not ready for prime time, and it may never be, but to say it is a ridiculous notion puts one in the same league as those who said that powered flight was ridiculous. And that would have been most people prior to 1903. Wouldn’t they be surprised to learn that today people can fly from Austin to Melbourne, Australia, for example, with more than 400 other people, in a little over 17 hours, with only one stop, at more than 35,000 feet, while having a glass of wine and enjoying a movie at their seat? Or sleepin
The overall load factor of 100 passenger per train for the Hiawathas may be acceptable to Amtrak because states are underwriting the cost; but what about the public’s interest? Shouldn’t Wisconsin and Illinois promote public goals such as mobility, safety, fuel conservation and emission reduction, and highway congestion mitigation with rail travel? Weren’t these underlying justifications for maintaining and improving rail passenger service between Chicago and Milwaukee?
The load factor is a performance measure that can be used to identify problems and opportunities. It measures how well goals are achieved. I have proposed a pricing strategy, not for the purpose of improving a measure; but for achieving goals represented by the measure.
Fuel conservation and traffic mitigation can be achieved in a small way, given the present scale of operation, by diverting travel from highway to rail. If lowering off-peak one-way fares would double ridership, filling more of the seats already available in the fixed consists running between Milwaukee and Chicago, fuel efficiency would rise to a respectable 92 passenger-miles per gallon. Furthermore, daily ridership, much of it diverted from auto use, would increase from 1,400 trips to 2,800 trips.
Since multiple occupancy vehicles would be unlikey to switch, 100 vehicles would be removed from I-94 in the hour the train ran. This represents only a small 1.67% of capacity, a little less than two cars a minute, for a 3-lane roadway.
Reduced monthly and 10-ride tickets have been offered for a long time. The monthly ticket price of $321 would seem to be instrumental in attracting over 300 passengers on #330 and #339 and represents $7.30 a ride for 44 trips. This is quite a bargain compared to the one-way fare of $21 that seems to me to stifle use. This is not congestion pricing; and the ridership amounting to 43% of the total impacts revenue.