There is no more pure joy than RailFanning.

This train (MDU RMM) is kept on the Madurai platform way before the departure time of 12:40, so if you come early (~1 hour before departure), you can get a nice window seat, and try getting a seat to your left (direction MDU RMM) to avoid the sun. The train will be quite packed by the time it departs Madurai, and majority of the passengers get down at station PMK. And after station RMD, this train runs quite empty.
Once the train approaches the final phase of it's journey (way before the pamban bridge), you can spot the sea far away on both the sides of the train, and as the train progresses, you can notice the sea shore...
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getting closer and closer towards you. Just before the train enters the bridge, you can spot many peacocks on the side of the tracks. Once you enter the bridge, (track speed limit: 15 kmph), if you look down, you can notice the sea water gushing with pace in a certain direction, and if you focus fully down, it's almost scary / thrilling at the same time ... makes you wonder how in the world did they construct the bridge in the middle of sea. You also have a wonderful view of sea all around. Even after you cross the bridge, before arriving at RMM, the sorroundings would be very pleasant with white beach sand dunes/palm trees/coconut trees... See the attached pics. You almost feel like you're strolling on a beach, but you're on a train.