I agree partially. Train board with source/destination official language and Hindi/English should be present in IRI. But the pic need not be restricted to 'only' these 4 languages.
On a real train board, the space is limited and it will be cumbersome to include all languages.
But this is just a website and we don't have such space restrictions. So, we can be as inclusive as possible.
A...
more... train from HWH to MAS covers many more stations in AP and Orissa than West Bengal or Tamil Nadu (and most trains in fact won't halt anywhere in Tamil Nadu except Madras). So, restricting the train board language to just Bengali or Tamil is not good as there will be a large number of Telugu and Odiya passengers also boarding the train on the route.
I feel the source/destination languages and Hindi, English board pic should be mandatory. But if there are pics available with other languages, there is no harm in including them. Same goes for the train names.