The search operation was triggered in the wake of tracking of Kalita's phone two days back which hinted that he had called someone in the city.
"Later it was found that someone using Kalita's phone had called up a public booth located at the railway station here," a senior official said.
"It has not been possible to make any headway as hundreds of people throng the PCO daily," DCP Nitinjit Singh said.
Police still searched a number of hotels and lodges near the station "but in vain," he said.
RPF inspector Barun Kumar Behera and GRP inspector Smruti Ranjan Kar too replied in negative but said an alert had been sounded and vigil was on.