Armoured trains
https://www.rbth.com/economics/2014/06/03/the_armoured_trains_that_turned_the_tide_of_the_russian_civil_war_35699
Armoured trains
https://www.rbth.com/economics/2014/06/03/the_armoured_trains_that_turned_the_tide_of_the_russian_civil_war_35699
would it tip over if the guns all fired at once?
You gotta shoot half the guns in the opposite direction. Yes, friendly fire was common.