At the stroke of midnight on January 1, 2000, the Y2K bug was supposed to turn the world topsy-turvy by wiping out all computer data and freezing all electronic devices. The clock struck 12, and nothing happened. But on Saturday, more than a decade later, a similar virus attacked the Western Railway and its flagship train, the Mumbai-Delhi Rajdhani Express.If the problem back then was 1999, this time it was the number 999. The commotion surrounding the Rajdhani as it waited to depart from Mumbai Central's Platform No 1 was quite unusual, even for Diwali season.Hundreds of passengers, who would have been upgraded from the waiting list to confirmed berths, were desperately trying to find out their reservation status. They dialled the enquiry at 139. They searched for updated charts normally posted at the train door, and on the platform, but found none.When the Rajdhani left for Delhi , at 5:13, 33 minutes later than scheduled, they were left stranded at the station, not knowing whether they had berths on the train or not. The problem, it later turned out, was a curious one.The online reservation system of the Indian Railways, managed by the Centre for Railway Information Systems (CRIS) allows only 999 e-tickets to be reserved per train. This number was considered a comfortable failsafe because the demand for online tickets had never exceeded 600, even at the busiest times. On Saturday, however, the Diwali rush pushed this demand to 999, and then into four digits. The moment the 1,000th ticket request was processed, the Passenger Reservation System (PRS) got confused, and promptly came crashing down.“We could not foresee that e-tickets would ever reach 1,000. This number was beyond all our estimates when the software was created. Today, the moment 999 was breached, the program developed a bug and starting behaving abnormally. No further upgrades were possible on the chart after that,” Ajit Jain, CRIS’s General Manager (Western), told Mumbai Mirror.“A special team of engineers has been constituted to look into the matter and find remedies,” he added.The genesis of the problem, said a senior Railway official who asked not to be named, lay in how the chart preparation for the train, which normally begins at around 1:30 pm for a 4:40 train, did not start until after 3 pm.“As a result,” he said, “a lot of people were booking berths online at the eleventh hour, until long after the system should have allowed them to. This drove the numbers into a hitherto uncharted territory.”By the time the Railways realised what was happening, there was about an hour to go for departure. CRIS was informed, but it was too late to fix the bug or try to retrieve corrupted data. The train was finally released with the manual (or skeleton) chart, updated at 8 pm on Friday.“There was chaos,” said Aman Acharya, a student with a ticket for Kota who could not board despite a quota berth because his name was not on the skeleton chart. “There were many who didn’t know what to do.”Divyesh Thakur, another student, added: “No one was able to check the status on the helpline number or the website. It was a panic situation. The RPF came out to control the crowd.”Since almost 30-35 per cent changes on the chart take place on the last day due to late cancellations, initial estimates by the Railways indicate that a few hundred people may have been affected. “After investigations, we will decide on refunds, or other remedial action,” an official said.