class Train
  attr_accessor :station
end

class Station
  attr_accessor :name

  def initialize(name)
    @name = name
  end
end


station = Station.new('Москва')
train = Train.new
train.station = station

puts 'до изменения'
puts train.station.name


station.name = 'Москва товарная'
puts 'после изменения'
puts train.station.name



puts "station.object_id: #{station.object_id}"
puts "train.station.object_id: #{train.station.object_id}"