The curious case of Chokalingam

Chokalingam aka Choku was just another signal operator in the mammoth Indian Railways. He was a resident of the Ambattur Industrial estate area in Chennai. Once returning home in his bicycle, he met with a freaky accident that gave him a fractured hand. It took him 6 months to recover. During the 6 months at home, Choku enjoyed the sceneries of smoke and fumes from the nearby industries. Naturally he was relieved after being recovered and reported to work finally. He was in the night shift and as usual took charge of the lonely signal at the outskirts of Chennai. Choku's comeback day turned out to be a nightmare. That day the Blue mountain express derailed near his signal. Fortunately very few people were injured. Immediately an investigation was triggered off.


Railway police official Raghavan lead the investigation. Raghavan summoned Raman first for interrogation. Raman was the engine driver of The Blue Mountain express that day. According to Raman, Choku had shown green lights. And as he was about to cross the signal he noticed another train coming straight at him from the opposite direction. Raman made a last ditched effort to stop the train to avoid the collision and it derailed. Though Raman was cogent, Raghavan seemed to be inconclusive. He called for Choku next.

Choku claimed that he showed the Red lights but for some reason the Blue Mountain did not stop. Choku added that Raman might have lost control due to a lapse in concentration. He added that it could have been worse if there had been a collision. Both Choku and Raman's claims were persuasive. Raghavan realised that the case was not so easy as he thought. He decided to take both Choku and Raman for a polygraph test.

First it was Choku's turn to take the polygraph test. He passed the test successfully. Now Raghavan had a clear suspicion on Raman. To Raghavan's astonishment, Raman also passed the polygraph test. Raghavan clearly had a job in his hands. Raghavan decided to question both Choku and Raman together. As the interrogation was steaming on, Raghavan was penning down some points. All of a sudden, he dropped his pen by mistake. Choku picked it up and as he gave it to Raghavan, said that the pen was cute and has got a nice shade of red. Raghavan's eyes lit up immediately.

The next day he attached the Doctor's certificate to the case file and called off the investigation. Choku was fired. The certificate confirmed that Chokalingam had acquired color blindness. Raghavan realized Choku's plight as soon as Choku called a Green colored pen, Red. While Choku was recuperating from his fracture at home, his body had obtained abnormal amounts of lead, thanks to the industries nearby. Unusual amounts of lead had caused the Red/Green type of color blindness in Choku.