Shan-e-Bhopal - तेरी खूबसूरती से नजर नही हटती, नजारे हम क्या देखें - ललितपुरी रेलफैन

Carrying phone is possible but we don't use it on duty. If the train has stopped, you can get down and use it.

Didn't know the Rule.
But i have seen LP talking to Phone when train was standing at Ballia,
A LP took Photo of Tejas WAP 5 at Ballia that too when train was standing.

So it clears that LP/ALP do have phones but most probably they dont use while running and if train is at some station then they can use.