TEHRAN, Iran—Iran’s railroad system came under cyberattack on Friday, a semi-official news agency reported, with hackers posting fake messages about alleged train delays or cancellations on display boards at stations across the country. The hackers behind the strike were apparently trying to be funny, and along with messages saying “long delayed because of cyberattack” or “canceled,” they urged passengers to call for information, listing the phone number of the office of the country’s supreme leader, Ayatollah Ali Khamenei. The semiofficial Fars news agency reported that the hack led to “unprecedented chaos” at rail stations. No group has so far taken responsibility for the incident. Earlier in the day, Fars said trains across Iran had lost their electronic tracking system. It wasn’t immediately clear if that was also part of the cyberattack. Fars later removed its report and instead quoted the spokesman of the state railway company, Sadegh Sekri, as saying …