Transit cards, debit and credit cards, and mobile wallets are replacing cash. Covid-19 accelerated this transition. However, some passengers do not have access to a bank account or credit card, and many do not own a smartphone or have internet access, potentially limiting their access. There have been few studies of the effects of cash removal and only limited attempts to understand key dimensions of the problem conceptually. This study aimed to: i) systematically review the literature on cashless fare implementation; ii) tabulate the key benefits and disbenefits of different fare payment types; iii) categorize and re-conceptualize the equity groups most vulnerable to exclusion due to cash removal; and, iv) understand the experiences of two early-adopter cities–London and Amsterdam. Most of the previous research has focused on the benefits, not disbenefits, of cashless fare payments. London and Amsterdam provide examples of benefits realization and measures to mitigate the effects of exclusion on key equity groups. Both cities gained significant benefits in the transition but mostly ignored exclusionary impacts. The paper develops a new conceptualization of "the excluded" to help operators understand those who may be impacted. This involves the digitally-excluded (those excluded due to lack of access to alternative digital payment methods) and the self-excluded (those who choose to exclude themselves, due to the mental and physical effort required to adopt alternative methods). Future research needs include the scale and costs of exclusion and the efficacy of particular mitigations to ease the transition for equity groups.