Chennai, Sept. 13: At least 15 persons were killed and over 50 injured late tonight when a passenger train rammed into the rear of a stationary train in Tamil Nadu.

The accident took place near Arakonam, 70km from Chennai. A railway official who reached the spot put the toll at 15 but said the number could rise. Official sources put the toll at eight.

The stationary passenger train, two bogies of which got derailed, was headed to Katpadi, a station where many passengers from eastern India get off on their way to Vellore for medical treatment. The other train was bound for Vellore Cantonment and one of its bogies jumped the tracks under the impact of the crash.

Train traffic on the busy southern Indian route was disrupted after the crash.

“The toll could go up as more people are trapped and many of the injured are critical as the impact of the collision was heavy,” the railway official said.

“Seven bodies have been found and 17 persons have been rushed to hospital. There is a likelihood that more passengers are trapped in the derailed bogies. We have rushed rescue teams from Chennai and nearby districts,” state DGP K. Ramanujam had said earlier.

According to railway officials, the Arakonam-Katpadi local was waiting for a signal at Sitheri railway station after it had left Arakonam at 9.20pm.

An EMU (electric multiple unit) from Chennai Beach to Vellore Cantonment, which had left Chennai at 8pm, moved on the same track and rammed into the waiting passenger train at 9.25pm.

At least two bogies of the Arakonam local and one bogie of the EMU were derailed.

Railway officials suspect a signal malfunction as the Chennai train would not have been on the same track as the waiting train otherwise. Both trains had crossed the Arakonam junction, which is always manned.

The mishap resulted in the cancellation of many outbound trains from Chennai to Karnataka, Kerala and western Tamil Nadu. Inbound trains to Chennai on the same route are unlikely to reach the Tamil Nadu capital in the morning, officials said.

According to railway sources, the driver of the EMU and the guard of the stationary train have died. The injured were taken to government hospitals in Arakonam and Vellore and the CMC Hospital in Vellore.

Since Arakonam is a busy junction, railway employees were able to reach the accident spot, 4km away, quickly. A relief train from Chennai has also been rushed to spot. Heavy rain was hampering the rescue effort.

In Delhi, home ministry sources said at 11pm that two teams of National Disaster Response Forces were on their way to the collision site with rescue equipment. Television reports said navy personnel had also joined the rescue drive.

Sources said railway minister Dinesh Trivedi was expected to visit the site.