How much carbon does the average diesel-powered (not hybrid or diesel-electric) freight train engine emit per ton-mile?
no expert on the rail industry but i dont believe any US company uses a strictly diesel freight train any more. they have all been diesel electric for awhile now. as far as carbon they should still be lower than a comparable amount of semi's
All diesel locomotives actually are now self-generating electrics. The diesel turns a generator that powers YOOOOJ electric motors geared to the drive wheels. IOW the electric part is the transmission between the engine and wheels. As for carbon output Assume 0.4 # of fuel per horsepower per hour. Assume the engine is run at about 50% most of the time the freight train is cruising. So for a 7000 hp locomotive, that'd be an average power output of 3500. So far the algebra gives us 1400 # mass of fuel used every hour. Most freight trains I've seen run like 4 locos, maybe more if it's a really long consist and there're more inclines to pull up. So that'd be like 5600 # of fuel for every hour that train is moving. But wait! Remember how much stuff that train's hauling! It's literally HUNDREDS of semi trucks worth of stuff, so to complicate this, you have to also know the length of run (in hours) and the load so you can get the carbon output per ton of cargo. After all that you must figure the percent by weight of Carbon in diesel fuel. Sorry, but I'm not doing that homework. Good question, BTW. Also, I did this calculation in my head for a commuter train last year and figure that the equivalent fuel mileage is like 50 mpg per person. Sure beats commuting in the family Status Urban Vehicle, huh!
