In an emergency, they could act as back-up for each other.
He and Park Chu-young will act as back-up for Giroud and Podolski for the near future.
Davies, who will act as back-up wicketkeeper to Matt Prior, is the only member of the touring party uncapped at Test level.
A further risk is the lack of specialist fly-half cover on the bench where Alex Goode, who plays full-back for Saracens, will act as back-up to Farrell.
Six will act as back-ups and 24 will take charge of the games.
Jonny Bairstow, as well as battling to reclaim the number six spot, will also act as back-up wicketkeeper to vice-captain Matt Prior.
Although Taylor has not made the full squad, he is included in a 17-man England Performance Programme line-up, who will tour India for a month from mid-November and act as back-up for the main party.
England have also named a 16-strong performance squad, which will fly to Australia on 14 November and act as back-up to the main party, playing three-day matches in Brisbane and Perth as well as undertaking training and conditioning work.
George Witt, the chief pit marshal for the race, said that the policy of the circuit was that in cases of fire, two marshals must attend and a further two act as back-up in case the first pair's extinguishers were not effective enough.
In general, the integrated protection or the substation area protection usually acts as back-up protection of substation, especially in high voltage systems.
The system has two types of standby robots which acts as back up unit in case of failure of any operating unit and immediately put in place of broken down robot.
