If you entered the wrong transaction password then IRCTC eWallet will be disabled/disappeared after 3 attempts and it will enabled automatically after 24 hours but prior using the IRCTC eWallet first get a new transaction password using forgot Transaction Password link and you will get a new password in your Mail account associated with IRCTC account. If IRCTC eWallet option is not showing in payment options after 24 hours then you may write to firstname.lastname@example.org and call on customer care no 139.
Login after 24 hours in your account check if available eWallet as options.
How to Get New eWallet Transaction Password –
1. Login in IRCTC account
2. Go in eWallet Links – Click Change eWallet Transaction Password