Ok, Passenger modes of transit can be argued all day long. One equation that in no way offers any real debate is the efficiency of freight rail vs. tractor trailer freight.
Being the case that all of about 1-5% of freight right of way is even remotely subsidized, and the tractor trailer freight utilizes roads that are subsidized by cars and 10-40% by the Government there is already a vast and MAJOR imbalance. But freight rail continues because of its insanely capable performance.
Take the Powder River Basin for example and the coal that comes out of their to power the United States. Between the Union Pacific and Burlington Northern Santa Fe 47.3 Coal Trains a day came out of the area bound for various places in the country. The actual number coming out of the area often reaches 80. Some simple math with that and you get...
47.3 Trains x125 Cars each is 5912.3 Cars.
1 Tractor Trailer == 66% of a single freight car. (Carries 2/3rds of what a freight car does in coal weight)
That's 7863 Tractor Trailers not on the interstate.
7863 Tractor Trailers a day out of the PRB. 7863 cabs at 6 MPG (Very optimistic estimate!)
Average distance out of the area to various cities is about 600 miles, so lets take that and... that gives us about 100 Gallons of fuel for each Tractor Trailer, which makes 786,300 Gallons of fuel.
Trains use almost half the fuel that tractor trailers average. So if you figure out the mileage for these trains you get about 436,833 Gallons of Diesal. If you take all of the engines (47.3 x an average of 3.5) in use on the trains and you figure about (1400 gallons per tank, about 2 tanks probably) to get to destination you get about 463,540. With both estimates you end up with a very close idea of about what it takes to get the trains to where they need to be.
With that, fuel is about $1.70 a gallon, which leaves tractor trailers at $1,336,710 bucks. Even if they pay a bit more one ends up with about a half million just for fuel. With the freight trains you end up with $742,616-$788,018. So even if fuel costs go up you end up with the same ratio. Trains use a lot less fuel overall, and when you start adding the trips together, you get an exponentially increasing efficiency.
Now if one figures in the labor for 47.3 trains vs. the 7863 Tractor Trailer the costs get really scary. To put it simply, with fuel costs amounting for a minority cost of operations, rail operations in this country for a massive cost savings in energy at the power plants.
In addition to fuel costs one can also consider the fact that freight rail cars generally can be used longer alleviating the higher price, sometimes making them somewhat cheaper and sometimes slightly more expensive. Also the freight rail engines are utilized a lot longer sometimes 50, and tangibly could be used longer than that, also alleviating the extra expense of such a large vehicle.
One cost that does not scale well at all is the human factor. Tractor trailer freight companies pay nothing for infrastructure personnel, freight railroads however pay all of the infrastructure support personnel. This totals billions more than the respective competition.
One could also derive certain obvious and point blank facts. Subsidies give trucks an advantage, creating a higher at counter price for consumers. If trucks competed fairly and paid primary costs on their primary right of way (For instance they bore the majoriy or ALL of the costs of the interstates, at 36 billion per year) one immediately realizes the real disadvantage tractor trailers would have against rail. Freight rail operations have also been curtailed and bore a brunt and extensive (literally thousands more than tractor trailer freight) list of regulations. Tractor Trailer freight often time skirt and entirely ignore their taxes, costs, regulations, and laws. Another advantage that freight rail does not have.
The savings that could be accumulated for the United States by removing subsidies and directly laying costs back onto road freight comparable to what rail freight pays for their infrastructure the cost savings passed on to customers could measure in the billions, possibly the tens or hundreds of billions in merely 5-10 years. With the new cash flowing into rail freight the amount of infrastructure additions could be massive creating actual legitimate market relative jobs (vs. non-market related jobs with interstate maintenance and construction). These jobs would also be more stable and less likely to sports and elliminations of work such as interstates, highways, and other roads and their respective creation via politcs of pull.
In conclusion, freight rail is insanely efficient and cost effective. Further usage of such systems is highly encouraged. Futher road freight only increases cost with minimal advantages for time to market bonuses.
This of course boils down to a more positive and equalization of laws and regulations created be policy makers and legislatures in our city, state, and national capitols.
Sources for Energy Usage: