Yes, the story is definitely false. I looked into some details the first time I saw it on HN, seemed strange then, and it cannot be true. Radiation from the disaster could, and did, mess with electronics, but close to the disaster area. Most contamination is with alpha-decay elements, and alpha rays aren't going to make it from inside a train to a computer inside a building by the tracks. And yes, any living creature radioactive enough to affect electronics would be rapidly and painfully dying.

It's a funny story, but the physics is impossible, and there's several historically implausible details as well, so I'm comfortable saying it's made up.