New Delhi, Feb 23: Vacuum toilets seen on aircraft may soon be a reality on Indian trains if a trial-run of such toilets, to be installed in 500 coaches, is successful, a top Railways official said. Speaking at the launch of an application for railway vendors here, Railway Minister Piyush Goyal today conceded that vacuum toilets could be an alternative to bio-toilets, which he said had issues of bad odour and clogging. "After Lohaniji (Railway Board Chairman Ashwani Lohani) came to Railways, he took a decision on vacuum toilets. Some problems of clogging and bad smell had arisen in bio-toilets. While the engineering department has addressed some of the problems, changes have been initiated," Goyal said. Lohani added that the Railways would soon start installing such toilets in 500 coaches on a trial basis where "air draft" would be induced into the toilets to prevent bad odour from emanating. "One way to address the odour problem is to normally induce air draft into the bio-toilets, this will lead to proper suction. We have ordered these for 500 coaches and then we will access the result, then if needed, we will order more," said Lohani. A bio-vacuum toilet has a suction pump that reduces the requirement of water. Most vacuum systems flush with just half a gallon (2 litres) of fluid or less compared to bio-toilets, which require up to 15 litres per flush.