# Cluster of related (inheriting) transport classes and test program

class Transport
        def initialize (seatsPerCarriage,time)
                @spc = seatsPerCarriage
                @time = time
        end
        def getTime
                return "departs: #{@time}"
        end
        def getLength
                return 1
        end
        def getCapacity
                return @spc
        end
end

class Train < Transport
        def initialize (length, seatsPerCarriage,time)
                @len = length
                @spc = seatsPerCarriage
                @time = time
        end
        def getCapacity
                takes = (@len * @spc * 1.4).to_i
                return takes
        end
        def getLength
                return @len
        end
        def setLength (newLength)
                @len = newLength
                return nil
        end
end

class Bus < Transport
        def getCapacity
                takes = @spc + 6
                return takes
        end
end

class Plane < Transport
end

# =====================================

puts "I am running #{$0} from #{__FILE__}"
if __FILE__ == $0 then
        puts "Testing my train, bus and plane classes ...."
        services = [ Train.new(2,78,"06:38"),
                        Train.new(1,79,"07:48") ]

        services.push (Train.new 9,40,"09:45")
        services.push (Bus.new 61,"22:47")
        services.push (Plane.new 88,"04:37")

        services.each do |service|
                cap = service.getCapacity
                l = service.getLength
                puts "#{l} - We can take #{cap} at #{service.getTime} O'Clock"
        end
end

__END__

Sample output

WomanWithCat:kingston grahamellis$ ruby transport.rb
I am running transport.rb from transport.rb
Testing my train, bus and plane classes ....
2 - We can take 218 at departs: 06:38 O'Clock
1 - We can take 110 at departs: 07:48 O'Clock
9 - We can take 503 at departs: 09:45 O'Clock
1 - We can take 67 at departs: 22:47 O'Clock
1 - We can take 88 at departs: 04:37 O'Clock
WomanWithCat:kingston grahamellis$