A phone can connect to only one network at a time, whether wifi or the wireless provider. Most of us will not be using the LCS wifi on our layouts anyway. I recommend a separate 10 inch or larger android or Ipad tablet to show a nice view with the camera.
I preordered one of the theatre cars but got impatient since they will not arrive for some time. I did some searching and found several mini wifi action cameras for model Drones and RC vehicles that work very well attached to a train. I tried the RUNCAM 2, Foxeer Legend 2, and Droneview wifi cameras. Their primary use is to record HD video (on a micro SD card in the camera) but they all provide a decent real time wifi link to your phone or tablet. The wifi link is reduced to probably standard definition quality, rather than the HD video that is being recorded. There is latency and some stuttering of the real time video. The wifi link has limited range (10m) and is not supposed to replace or interfere with the FPV tv link used to fly the drones. The wifi connection can drop out due to interference from other wifi devices causing delays in the picture to the camera. These 3 cameras all require you to connect to a non internet wifi network signal supplied by the camera, in the 2.4 ghz channels 1-12.
