Following the second world war Crosville had become part of the Tilling Group and this resulted in a more standardised system of route numbers being introduced which began to appear on most Crosville buses. The routes numbers used were numerical and were allocated in groups of 100s which related to the various Divisions of the company.
For a period after 1947, to distinguish the different places served or the various intermediate destinations, a letter was added to the route numbers (e.g. 101A etc.). However In some areas, especially around Crewe, the number of variations could amount to over 13 and the 207 service, for example, had variations between A-P with also W being used for a work peoples service.