Take it as given that the opportunity cost of train is car. (obviously, as by def. the next best alternative ;)
Assuming that on average you can get 10 km on 1 litre of fuel, in Switzerland at the current gas prices:1km = 0.151 USD and in the US, 1km = 0.078 USD.
At the current exchange rate this is more or less equivalent to the price in CHF, namely: 0.16CHF and 0.08CHF respectively.
Now we can explore the train costs with respect to car costs.
Paying tribute to old mate David,
"Double, double toil and trouble;
Fire burn, and caldron bubble." and ta-da!
In USA, the opportunity cost of 1 km on train cost is 0.66 CHF of 1 km by car but only 0.47 CHF of 1 km by car in Switzerland.
Of course, if you are a true baller boasting a Hummer, then the above may no longer apply.
However, as recession hit hard the USA, and keeping in mind that in 2000, 57% of households owned 2 or more cars, then assuming slightest amount of rationality within the jungle that we are living in, we can expect that people tried to make more trips with the environmentally friendly, fuel efficient cars of the wives... In this sense, the vehicle ingredient of the above calculations is no longer as heterogeneous, and shouldn't bias the USA-CH opp costs results.
Optimist's bottom line: Swiss trains are a good deal
Pessimist's bottom line: Swiss cars are "uber-piggy-bank-breakers