Railgun question

I have a little question on railguns:
Player A builds a railgun.
Player B sabotages the railway in the city that the railgun is stationed in.
Player B's infantry approaches the city.
I assume that the railgun cannot move,since it is clearly stated that it only moves on railways,but can it still bombard the infantry? Realistically ,it must be able to do so,but I would like to be sure.
Thank you in advance!