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Overnight lane closures will be in place this week while Network Rail crews clean up Luton Arches in Chatham.
Workers will be clearing gutters and down pipes and cleaning up brickwork between 9pm and 5am, starting on Monday night.
A Network Rail spokesman said workers would aim to finish the job in three nights, but that work could continue for the rest of the week.
Online community group Future Chatham contacted Network Rail to request the arches were cleaned, and says it is working with Arches Local, Medway Council and Network Rail to regenerate the area around Luton Arches.
A statement on its website said: "The repairs of the guttering at the Luton Arches that Network Rail will be carrying out are a step further to improving the appearance of the rail bridges.
"The white and green muck on the viaduct walls are indeed an eyesore, and we are glad that we have contacted Network Rail to bring their attention to this issue.
"These guttering replacement works are just the start of a long-term regeneration in the area that Arches Local and ourselves will be driving to achieve."