It's the Coronation of King Charles III at Westminster Abbey in central London. And it's the responsibility of TfL to make sure that thousands of people can get to the procession and back safely. Removing street lights, diverting over one hundred roads, managing foot traffic and fixing any surprise engineering issues, the teams must work to military precision in order to keep the day running as smoothly as possible. But protests have been scheduled and there are reports of terror threats.In west London, engineers at the depot get ready for some ballast replacement work, moving tons of replacement rail in time for Northern line engineering works in the evening. And at Acton Town Station, an 85-year-old train is temporarily being brought back into service. The art-deco Piccadilly line train will be running alongside the regular service, which means it must keep to a strict schedule in order not to upset the controller or the thousands of commuters using the line. The old train is mechanical and susceptible to the heat, which might throw a spanner in the works.