1.   Railway authorities said they wanted to question four signal operators who fled after the accident.

2.   At least three railway signal operators working at the time of the accident fled the scene, authorities said.

3.   Four signal operators working at the time of the accident fled the scene.

4.   Four signal operators working at the time of the accident fled the scene, and their whereabouts were unknown.

5.   He is expected to question three railway signal operators working at the time who briefly fled the scene.

6.   Mani is expected to question several railway signal operators working at the time who fled the scene.

7.   Mani is expected to question three railway signal operators working at the time who fled the scene.

8.   Mani is expected to question three railway signal operators working at the time who briefly fled the scene.

9.   One other signal operator was still missing, officials said.

10.   Railroad officials are investigating how signal operators sent the two trains toward each other on the same track.