Not sure where cynwoody found the conversion figure from mph to ft/sec but it is in error.
Actually, that part of my calculation was dead on: (70 miles per hour * 5280 feet per mile / 3600 seconds per hour) = 102.7 feet per second (or 31.29 m/s).
Where I went wrong was in assuming the formula ke = 0.5*m*v**2 actually yielded foot-pounds. My next step was to ask Google, what is 79053.3 foot-pounds in kwh? Garbage in, garbage out, LOL!
If you instead take the bowling ball's mass in kilograms and the train's velocity in meters / second, the calculation is 0.5*6.804*31.29**2 = 3330.8 joules, or 2456.7 foot-pounds, in close agreement with your result.
The watt-hour equivalent is a puny 0.925 watt-hours. It would take a lot of speeding bowling balls to keep you warm in a 2015 winter.
“...Where I went wrong was in assuming the formula ke = 0.5*m*v**2 actually yielded foot-pounds. ...”
Getting the units correct is a recurring nightmare for scientists and engineers. So are American/English measurement conversions; metric is much simpler. The only reason the Anglophone system hangs on at all is because of early British and American dominance in aeronautics and astronautics.
Considerable chunks of my struggle through higher education were taken up by aeronautical engineering. I’d estimate that during my first trimester in grad school (courtesy of USAF), I spent 1/4 to 1/3 of my time converting from one measurement to another.