Surface and underground train times (uk)?

Put simply it means that you've got from18.47 to 19.58 to get from Waterloo to Liverpool Street. There are several routes you can take - e/g Waterloo to Bank then Central line to L/Street OR Bakerloo line to Oxford Circus thence that Central line again - a lot could depend on if there are any delays on the tube, but all being well you've got plenty of time to make the journey - even by bus if necessary!