Chaos was brought to London's railways system on the morning of 3 March after a fire broke out under a disused railway arch near South Bermondsey train station.
Fire-fighters were called to the blaze at 3.45am but London Bridge, Charing Cross and Cannon Street stations were all still closed by rush hour.
Numerous national rail services operating out of London Bridge were severely delayed with other trains being diverted through Victoria station.
The cause of the fire, which was under control by 1.30pm, is still unknown and was made more difficult to deal with due to the presence of gas canisters, the London Fire Brigade said.
Train operator South Eastern said it hoped services would return to normal by the evening but passengers should expect some delays and cancellations.