Machines can be used, at times when training DC I have used them almost exclusively. It's not optimum, but can be done.
Just look for machines that you can target the intended muscle group, use dumbbells when possible and I'd limit the amount of rest as intensity will be decreased a bit due to not having to balance the weight as the machine does it for you.
Overload and progression are the key to gaining size/strength.
Does your gym have a Smith machine?