The above article argues whether or not placing a penny on train tracks can derail a train. For this claim we will evaluate two of the six principles of scientific thinking.
Firstly, we will evaluate the "extraordinary claims" principle. Is the evidence as strong as the claim? In this case there has been no such evidence to support this claim and no experiments have actually tested this claim. Basically one person said it has occurred in the past and people started to believe it. Tragically, people have died trying to set pennies on tracks to either "flatten pennies" or "derail the train".
The second principle we will evaluate is that of replicability. In this case, the results would easily be duplicated if a proper experiment was set up. To date, no other scientific studies have reported the same findings as this "urban legend".
An alternate explanation that a penny derailed a train could be that of the age of the railroad track. A person could have laid a penny on a set of tracks that happened to be old or not functioning properly. After, finding out that a train had been derailed on that certain track the person could have claimed that it was solely due to the penny that had been placed there. This does not take into account the reliability of the train tracks nor the fact that user error by the conductor could have played a part in the derailing of the train.
The principle most useful for evaluating this claim would be replicability. One could formulate an experiment to be conducted to test this claim. We could pick 10 sets of train tracks at random and place pennies along the tracks. Then we would have trains running at the same speed down the tracks all for the same distance. Based on how many trains got derailed we could test this claim and see if it is indeed true or false.