The C.T.A. could increase ridership by temporarily putting branch libraries in vacant retail space in stations.The libraries would have expanded hours or even be 24/7 so they would attract patrons from a wide area including those that rarely use the C.T.A. currently.
An expanded hour department of revenue facility might be a money maker.I know you can pay for many things on line or at currency exchanges,but still many people might want go to an official facility.Again this would be in C.T.A. stations and could bring additional riders.
A version of the C.T.A. gift store could be placed in some stations.Cheaper umbrellas would be needed for impulse buying during rainstorms.
Putting art exhibitions or mini museums in stations could also bring in more riders.