General Discussion

caraher

(6,359 posts)

41. MPG isn't a good metric

Sat Nov 23, 2013, 01:10 PM

Nov 2013

For land transport, rail is going to be the efficiency winner, mainly because trains have lower rolling resistance (steel wheels on steel tracks lose less energy to constantly deforming the wheel at the point of contact than rubber on pavement) and because they present less frontal area per unit cargo (so a smaller fraction of the energy goes into moving air out of the way than in moving freight). This is all presented very clearly by David MacKay

The appropriate metric is energy cost per unit mass moved per unit distance traveled, e.g. (gallons fuel used)/(pounds moved * miles traveled). Put in MacKay's favored physics units, that would be kWh/(ton * km):

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The average 18 wheeler loaded at 80,000 lbs gets about 7 miles per gallon. [View all] livingwagenow Nov 2013 OP

Let's localize and kill the international behemoth corporations. LuvNewcastle Nov 2013 #1

Roger that. The 2000 mile potatoes: trof Nov 2013 #2

Perfect example of shipping food that used to be grown locally. livingwagenow Nov 2013 #3

When I was in New Mexico last year brer cat Nov 2013 #16

Yup. I lived in Yakima, WA for years. Apple Capitol of the WOrld Heddi Nov 2013 #45

It is insane. I support Localvores! trof Nov 2013 #70

When I was in England and Italy thecrow Nov 2013 #4

Things move by rail, mostly Spider Jerusalem Nov 2013 #26

A little off-topic, but Art_from_Ark Nov 2013 #36

One and the same, yes Spider Jerusalem Nov 2013 #46

Actually, the UK (and the EU) uses rail far less than the USA muriel_volestrangler Nov 2013 #44

Thank you. A HERETIC I AM Nov 2013 #52

And you were sitting in my car.... where? thecrow Nov 2013 #62

LOL...yeah...sure. A HERETIC I AM Nov 2013 #65

Nope. Didn't see that. thecrow Nov 2013 #69

I'm sure distance has something to do with that... Wounded Bear Nov 2013 #61

It's a self limiting. sendero Nov 2013 #5

We may have to learn to eat fruits and vegatables 'in season' again. trof Nov 2013 #12

Frozen bagged vegetables may have a smaller carbon footprint than fresh at a farmer's market FarCenter Nov 2013 #6

That's pretty damn good actually Rstrstx Nov 2013 #7

i was thinking the same thing dembotoz Nov 2013 #14

Yup. cthulu2016 Nov 2013 #29

Great post dreamnightwind Nov 2013 #8

Willie Nelson gets it ... Scuba Nov 2013 #9

I guess it depends on how you look at it. Glassunion Nov 2013 #10

Hybrid diesels can do 12 MPG. karadax Nov 2013 #11

It's not just a matter of investing...it's how to get them on the road... cynatnite Nov 2013 #20

The truckers I've talked to say the same thing about bigger engines getting Egalitarian Thug Nov 2013 #35

How well do these Hybrid diesels scale up to be able to haul 80,000 lb truck cross country? RC Nov 2013 #58

Train engines are hybrid diesels. lumberjack_jeff Nov 2013 #64

Actually, no they are not. RC Nov 2013 #66

People disagree on this point, but after doing some research, I think you're right. lumberjack_jeff Nov 2013 #68

Similar to pre-nuclear submarine technology. I understand Eleanors38 Nov 2013 #72

We're doing our part... bvar22 Nov 2013 #13

7 mpg is very generous. 4dsc Nov 2013 #15

The "range" of class 8 trucks is between 4 & 7.5 MPG A HERETIC I AM Nov 2013 #55

While rail cars sit idly on the tracks... tosh Nov 2013 #17

It's possible the rail cars are moved at night Not Sure Nov 2013 #33

Good point. tosh Nov 2013 #39

Shipping by rail is more fuel efficient Yo_Mama_Been_Loggin Nov 2013 #18

It's also much slower than truck and can't get to the places that trucks can. n/t cynatnite Nov 2013 #21

Much of it was duplicate track laid by competing railroads... Not Sure Nov 2013 #34

Not every Class I is interested in maintaining its moneymakers. Brickbat Nov 2013 #53

You're right Not Sure Nov 2013 #56

It's shameful how bad it is. Brickbat Nov 2013 #57

I'm sorry to hear that Not Sure Nov 2013 #63

not really hfojvt Nov 2013 #54

My husband has been a truck driver for 17 years... cynatnite Nov 2013 #19

I've been in trucking for 25 years CANDO Nov 2013 #22

My husband got a truck with 3 million miles on it one time... cynatnite Nov 2013 #24

It's not trucks vs. rail, it's trucks + rail Not Sure Nov 2013 #32

The average American car gets 24 miles to the gallon. Spider Jerusalem Nov 2013 #23

Can you cite your statistic? Agschmid Nov 2013 #27

here: Spider Jerusalem Nov 2013 #28

Thx. Agschmid Nov 2013 #30

I love to buy American and I look for it when I shop. I 'll pay a premium for it. badtoworse Nov 2013 #25

could large cities like NYC Revanchist Nov 2013 #31

If they were well planned yes, but none of them are so, no. Egalitarian Thug Nov 2013 #37

Your post is a little misleading. My Freightliner's GVW was 26,000 lbs. That's JUST the tractor. cherokeeprogressive Nov 2013 #38

Late model tractors pulling a composite dry van will scale 46,500. Ikonoklast Nov 2013 #71

A bigger problem is F-150's that get 15mpg and hold four people are flying off the shelf taught_me_patience Nov 2013 #40

MPG isn't a good metric caraher Nov 2013 #41

Agreed. That's the metric to use. nt stevenleser Nov 2013 #43

a truck still has to take if from rail facility FatBuddy Nov 2013 #48

Sure caraher Nov 2013 #49

they do that for lots of goods FatBuddy Nov 2013 #50

The big picture has to involve creating different jobs caraher Nov 2013 #67

Capitalists care about one thing only - profit TBF Nov 2013 #42

if you have it FatBuddy Nov 2013 #47

In the overwhelming majority of cases. A HERETIC I AM Nov 2013 #51

7 Gallons a Mile for That Big Thing? On the Road Nov 2013 #59

Compare that to the 4000 pound SUV carrying the 200 pound human. Archaic Nov 2013 #60