Creating equity through positive cash flow property’s

Hi, I am halfway through reading Steve's book so may be jumping the gun, but having read all the funadmentals of positive cashflow property, can someone tell me how it is that you create enough equity in these properties to borrow more to buy more? Given that in some circumstances the positive cashflow property might be in a low capital growth area. Surely bringing in $50 net cashflow a week isn't going to create a heck of alot of equity with the bank?