Could be that they noticed a drop in the number of people stopping by the restaurant to watch trains (in person) and then eating lunch or dinner.
If people want the cameras to return they should let the owners of the restaurant know this (phone, email, on the restaurants Facebook page, in person, etc.) since its safe to say they won't return unless people push for their return.
In my view it was probably a mistake to take down the cameras, since they probably provided a certain amount of free advertising for the restaurant.