'Delivery is 99% of the project'

Exclusive: inside London Overground’s £6m rebrand

With six new lines, and millions of printed products, the rebrand will cost TfL £6.3m
With six new lines, and millions of printed products, the rebrand will cost TfL £6.3m

Tenders for Transport for London’s (TfL’s) £6.3m London Overground overhaul will go live later in 2024, with 113 stations and six lines requiring totally new signage. Printweek spoke to TfL’s head of design Jon Hunter to find out more.

On 15 February, TfL unveiled its plans to transform its Overground network.

The rebranding, due for completion by the end of 2024, will see the Overground’s complex existing network of rail lines simplified into six distinctly coloured lines, each named after historic events or landmarks of each area.

The Overground network has so far been uniformly represented in bright orange since its inception in 2007. Extended to East London in 2010, South London in 2012, and further into North London in 2015, it had grown into an orange spaghetti proven by TfL’s own research to confuse passengers.

Hunter said: “[The 2015 extensions] were a tipping point – we had created a network which was overlaid in places, and it started to become confusing. 

“It had just reached the point where we needed that separation – and we needed it especially for real-time updates.”

Travel disruption on the Overground – a not infrequent occurrence – has so far had to rely on customers being able to identify the Overground’s routes in their head, and pin down which stations bookended the disruption. 

On a network with 113 stations, this could prove difficult.

“Now, by splitting the lines, we have a very similar approach [to the Tube system]: you have a specific line, and you’re using that to plan your journey. If you never take the Mildmay line, and only take the Weaver, you know which will impact your journey,” Hunter said.

The new Liberty, Weaver, Mildmay, Windrush, Suffragette and Lioness lines have required a total redesign of the maps, with around 30-40% more information to fit into the same frames.

“To keep costs as affordable as possible and proportionate, we haven’t increased the size of the signs,” explained Hunter.

“We’re just hanging the front vitreous [enamel] and our panels – not necessarily overly complex, but it means that every single sign has had to be reworked.”

As another cost-saving device, TfL has rolled the printing of much of its collateral into its usual biannual re-print. Its 4,500 quad-roll A0 maps, “quite a distinct, heritage size,” 4,500 A0 London rail and Tube maps, and four million pocket tube maps are usually printed every six months, with the rebrand timed to coincide with its normal order. Interior train signage, printed on Fire Resistant Panels (FRP) will also go up for tender.

All tenders will go live through TfL’s dedicated broker, Corporate Document Services (CDS), which deals with much of the public sector print in the Greater London Authority. Tenders will be available on the dedicated CDS portal at least three months before each project is delivered, with the rebrand due for completion by the end of 2024.

Altogether less ordinary, however, are the many thousands of vitreous enamel signs – a craft with roots traceable to the 13th Century BC – and the PVC-free vinyl adhesive covers, printed digitally and assigned to each enamel sign, to allow for installation ahead of the big reveal.

Enamel, screen printed and then fired, is an unusual choice for signage – but has outstanding resistance properties, explained Hunter.

With no static cling, it is as close to self-cleaning as physically possible, he said, and has incredible UV resistance, giving a lifetime of 50 or 100 years for signs.

It does not come without its challenges, however: since the process’ industrial adoption in the 1850s, many of the pigments used have had to be retired – arsenic green, for instance – leaving a limited gamut.

This presented a challenge for Hunter.

“It’s not like mixing CMYK: we have to work extremely hard with our suppliers, and go through multiple tests to make sure the colours are repeatable and achievable across all media, before we colour-sample the enamel panel to ascertain our final CMYK values,” he said.

Reproducibility is vital, he added, as customers need to be able to rely on having that exact shade be consistent across the entire network to find their way.

Enamelling, therefore, has been joined at TfL by another rare craft: wet proofing.

“Again, it’s quite a dying art, but to be honest it’s the only way we can guarantee that the colours we’re producing are actually coming out the way they should on an offset press, or a digital screen or on enamel,” Hunter explained.

“So it’s quite a mix of contemporary and traditional products and materials we’re using here, to achieve a consistent quality approach.”

Only two suppliers of vitreous enamel of sufficient size for TfL’s needs remain in the country, AJ Wells and Link Signs, who screen print each pigment layer onto metal sheets before firing them in a kiln. The order of pigments must be chosen carefully, with each requiring a different temperature to fuse with the layer below.

Even after everything is printed, the challenge of installation will require careful orchestration, Hunter said.

“It’s the biggest challenge we face,” he said.

“It’s potentially one of the biggest re-signing exercises ever done in a live network environment, definitely in contemporary times.”

The Elizabeth, DLR, or Jubilee line jobs paled in comparison, according to Hunter, as they were isolated to a single line, or, in the case of the Elizabeth line, a line that was not yet live.

In order to not confuse travellers, TfL has determined to execute the entire rebrand over 48-72 hours.

“And we have to do it in such a way that the person using it on a Friday will use the same network on Monday, with everything working better than it did before,” Hunter said.

“Think of the hundreds of thousands of passengers that we’re moving – the choreography of this is pretty extreme. After the launch, we were relieved, thinking ‘At least that part’s done.’ But the delivery is 99% of the project.”

Most of the signage will be installed prior to D-Day, with the enamel signs covered up and tagged on digitally-printed adhesive wrap, ready for the reveal.

It’s still quite the task, but the team is confident, according to Hunter.

“[The rebrand] needs to make the Overground better – and our suppliers are definitely up for the job. 

“We have a really good team of project and programme managers looking into the logistics, doing trial runs, timing exercises and doing Amazon-style tests of how many stations a vehicle can visit in a night, so that everything is done as efficiently, quickly, and safely as possible.”