The scheme was promised by the mayor in his 2021 re-election manifesto, with the goal of making the network easier for passengers to navigate.
Seb Dance, deputy mayor for transport, said posters have now been put up in stations informing people of the plans and encouraging them to get involved.
The project is estimated to cost £6.3m over two years, but Mr Dance said the scheme was “very important”.
“When you look at the map...it can be a little bit confusing, so we would just want to make it more accessible for people who find the network challenging.
Mr Dance said: “Particularly on the very rare occasions when there is disruption on the network, it is extremely important that passengers get a much more focused set of information on where the issue is - so it will definitely help on that.”
The new posters, put up in Overground stations by Transport for London (TfL), tell passengers: “Over the next few months, we’ll be speaking to London Overground customers and different communities to understand more about the history of the network and the people it serves.
“As part of this, researchers from our partner agency, DNCO, a creative studio specialising in place and culture, will be travelling on the network speaking to customers about their experiences on London Overground.”
The posters warn that photography may be taken as part of the research and that passengers can tell the DNCO team if they don’t wish to appear in the photos.
Responding to a written question about the project from Elly Baker - a Labour member of the London Assembly - the mayor’s team said the majority of the scheme’s budget “will be used to update customer information”, including “updates to all digital information, station signage, maps and wayfinding”.
They added that following the initial phase of speaking with passengers, carried out by DNCO, TfL “will seek further views from the public later in the year on the shortlist of names for each route”.
Of the scheme’s total cost, £4.4m has been included in TfL’s budget for the 2023/24 financial year, with the remainder (£1.9m) forecast to be spent in 2024/25.
TfL has said it will work with the mayor’s Commission for Diversity in the Public Realm “to establish broad themes we'll use to guide the community engagement”, with that process set to include local groups and transport historians.
Services will not themselves be impactedâ¯by the name changes, TfL said, and London Overground will remain as the network’s umbrella brand, keeping its orange roundel.
The six distinct lines set to be given names are:
Highbury & Islington to West Croydon/Clapham Junction/Crystal Palace
Richmond/Clapham Junction to Stratford
Gospel Oak to Barking Riverside
Watford Junction to Euston
Liverpool Street to Enfield Town/Cheshunt/Chingford
Romford to Upminster