A strike is not considered legally as force majeure, since it doesn't usually prevent you from getting to work, but merely makes it either difficult or very expensive. There are no trains? Take a taxi. Or ask your friend to drive you.
If you can't commute (because, indeed, nobody wants to pay $500 for a taxi and few friends want to drive you to another city at 7 AM):
Contact your employer as soon as possible and explain why you can't commute.
Show that you've actually tried. “Sorry, I'll stay home today because it seems that train drivers want to go to a strike.” doesn't give a good impression. On the other hand, if you've actually at the train station and there is really no way you can get to work, your employer may accept it better.
If possible, commute, even if you'll be late. Staying at home is worse than being one or two hours late.
Suggest alternatives. “Would you like me to work from home?” or “I'm ready to work the next Saturday” leave a good impression.
Despite this, you may still suffer from strikes. In Belgium, strikes by train personnel cause many lay offs every year. In France, the fact that I had to have one hour commute while all of the other 100 employees had their own car was problematic as well when bus drivers were on strike.
In those situations, while the official reason for lay offs is not the fact that they were unable to come to work on a given date, this is still an element which may influence an employer to get rid of an employee. In other words, if you're in good relations with your employer, there are chances that you'll find a solution together (like telecommuting). If your relations are not so good and you are not in generally perceived as an irreplaceable resource the company should keep at all costs, the impossibility to commit to work can be among the reasons which will push the employer to fire you.
Another point to note is that some employers in countries/cities where bus/train driver strikes are common will be reluctant to hire a person without a car in the first place. Requiring a driver license for a position is legal, even when you obviously don't need one (for instance a company is close to a bus stop and your job doesn't require traveling).