From an initial standardised corporate image, several sub-brands emerged for marketing purposes, and later in preparation for privatisation. These brands covered rail networks, customers services, and several classes of new trains. With the size of British Rail's fleet, due to the time required to repaint rolling stock, in terms of the physical trains brand switchovers could be lengthy affairs lasting years. This worsened into privatisation, with the same services often using 3 or 4 different liveries.