The renaming of the Overground lines draws closer, indeed should be taking place next month. The original intention was for the changeover to be in August in conjunction with a new tube map, but that's not happened so technically it's late. That said, an awful lot of signage on the Overground has already been replaced, and there are two ways to tell this.
Firstly, if you look closely at a lot of Overground signage you can see the new signs underneath. This is Kensal Rise.
It's hard to get the lighting right for a photo, but the hidden slightly-raised lettering says 'Mildmay line' across the top, then the stuff about trains to Richmond and Clapham Junction in a smaller typeface, then a revised line diagram a bit lower down. What they've done is install the new sign and then immediately cover it over with the old sign printed on a sheet of vinyl. This is very clever because it means all the vinyl can be peeled off on launch day rather than signs being replaced incrementally over several weeks.
And secondly, the London Transport Museum Shop is already flogging off old signs that've been removed.
At time of writing they have 63 such signs available, any of which can be yours for a hefty price. For example the decommissioned sign from platform 2 at Shoreditch High Street is currently on sale (vitreous enamel/good condition/105 x 70 cm/14 kg) for £995. The original sign from Kensal Rise is also up for grabs, this time for £750, confirming that my first photo must show vinyl stuck over a new enamel replacement.
To save you asking, the cost of replacing all this signage is £2.3m, because a lot of miserable grumps put in FoI requests six months ago to check.
Of course the risk with covering signs with vinyl is that someone unofficial might peel it off, and this is indeed what happened along the Watford-Euston line a few weeks ago. Travellers at various stations were suddenly faced with signs showing they were travelling on the Lioness line even though that hadn't yet been launched. This was Kensal Green.
Previously the title would have said 'Bakerloo & Overground' but now we get two separate headings, each with a top strip in the correct line colour. Previously there was one line diagram but now there are two. Previously you'd change at Willesden Junction for two Overground line mouthfuls, but now it says change for Lioness line and Mildmay line instead. It's amazing how many subtle tweaks need to be made when six new line names are introduced.
TfL evidently weren't pleased with this unplanned reveal along the Lioness line because they've covered them all again. Fresh vinyls have been printed and these have been diligently stuck back over the new signs so that passengers still think they're looking at the old signs. So don't go to Kensal Green, Bushey or wherever expecting to see a new sign because you missed your chance. But do keep your eyes peeled across the Overground network because the new signs are increasingly ready and waiting for launch day, secretly hidden in plain sight.