London has this for children and OAPs (I think kids pay a token amount if they use trains...). For OAPs it's limited to after 930am (post rush hour). I think

London has this for children and OAPs (I think kids pay a token amount if they use trains...). For OAPs it's limited to after 930am (post rush hour). I think its good, but you have to be careful. London pay for this via Londons taxes. If whatever government you have isn't prepared to make up the lost revenue (and to do so indefinitely, under all economic/political conditions) you're dooming your transport system.