CHENNAI: While officials in the Railway ministry have gone to town about the speeding up of 600 trains from November 1, they have been tightlipped over the slowing down of more than 250 trains whose running time has increased from five minutes to 110 minutes.Trains from all zones have been slowed down, effective from November 1, but no intimation has been given to passengers. Data mining by TOI shows that for instance, the Rameswaram-Faizabad Express will now take 50 minutes more to cover its 2,900 km distance.The Chennai-Thanjavur Uzhavan Express has slowed down by 25 minutes, while the Lokmanya Tilak Terminus (LTT)-Gorakhpur is down by 1 hour and 15 minutes. The journey time of the Kolkata-Patna Express (13131) has increased by 1 hour and 20 minutes from November 1.After the `slow down', the average speed of trains like the Guwahati-Naharlagun Shatabdi Express and Secunderabad-Yeshwantpur Garib Rath has come down below 55 kmph, which is the benchmark for superfast trains. Indian Railways collects a `superfast surcharge' on the tickets for these trains and it remains to be seen if this will be withdrawn.Within the Southern Railway limits , sources said the running time of 20 trains has been increased 13 of them by five minutes and the rest by 1025 minutes.Railway officials say that the speeding up of many trains has happened at the cost of slowing down other trains, which is basically an optimising exercise. “In some areas, we have given extra mainte nance blocks because of which the trains have been slowed down. In North Frontier Railway , trains have been delayed due to the elephant corridor.There are some works going on in the Koraput-Jagdalpur section and a speed restriction has been imposed,“ the official said.In some cases, trains have been slowed down so that passengers can have a `convenient' arrival time.Giriraj Bissa, founder of erail.in which provides railway related data, questioned the transparency of Indian Railways. “Most trains have been speeded up by decreasing the slack time by only 5-10 minutes. But this has been publicised. However, the slowing down has not been circulated on social media or through press statements,“ he said.A Southern Railway official said the slowing down of these trains was unavoidable in order to maintain the superfast character of some trains.