The front car of every train is reserved for women. The kiosks are one of the best places in Cairo to make change, but some of the employees are a little uptight about accepting torn or taped banknotes. Even a 25-piaster note with a barely discernible tear in one corner will be turned away. Assuming you get a ticket, feed it into the turnstyle upon entering, and hang onto it until exiting. Intervals between trains varies throughout the day, but waits are never more than 15 minutes.
Breakdowns are infrequent, but trains sometimes linger at stations for no apparent reason.
Delays are also caused by riders holding the doors open for friends behind them, sometimes far far behind them. The two metro lines vary slightly. The underground platforms are comfortably warm in the winter and stuffy, humid and hot in the summer when the only breezes come from passing trains. The newer Shoubra-Cairo University line is better. Consider yourself lucky if your daily commute uses this line.