Fifty bendy-buses are ready to go back on the roads after a series of fires saw the 130-strong fleet taken out of service on Tuesday.
At least three bendy-buses have caught fire in the last three months
The manufacturers said some could be back on route 18 as early as Friday evening after engineers replaced and modified pipework.
A 436 bus was gutted by fire in Park Lane, central London on Saturday night in the third fire since December.
The whole fleet is expected to be back in service within a week.
Routes 453, 431 and 293 will benefit from the return of the first 50 repired buses over the weekend.
Hans Smit, managing director of manufacturer Evobus UK - part of the Mercedes group - said: "We sincerely apologise for any inconvenience to the public and bus
operators as a result of these incidents.
"In the interests of passenger and driver safety we had no other option but to withdraw the vehicles on Wednesday."