Four years ago TfL published a tube map with Morden in the wrong fare zone and had to reprint half a million copies. The error occurred when the trams were added to the map, because adding a new mode of transport is always tricky. This week they've added Thameslink to the map... and an eagle-eyed reader reckons there might be another error in southwest London. Has Tim spotted a serious blunder? See what you think.
All the new Thameslink stations are in their correct zones, so it's not that. But the problem is zone-related and affects Hackbridge, isolated on its little Zone 4 island. The map includes a white stripe immediately to the north of Hackbridge, labelled clearly at both ends as being in Zone 5. This suggests that travelling one stop from Hackbridge to Mitcham Junction involves passing through Zone 5. But in fact both stations are in Zone 4, so that's incorrect.
There's more. Follow Zone 5 to the left, past West Sutton and Morden, and the white channel magically morphs from Zone 5 to Zone 3. Ditto the thin white channel above the tram zone, which is definitely Zone 3 at one end but turns into Zone 5 at the other. Topologically speaking this is very wrong - the two zones shouldn't touch.
The underlying problem is the 'London Trams fare zone' which is grey. Grey zones are not allowed to touch each other at any point, otherwise their boundaries would become indistinguishable. This means the tram zone can only touch Zones 3 and 5, not Zone 4. Unfortunately Hackbridge and Mitcham Junction are both in Zone 4, which is grey, and Mitcham Junction has a tram stop which is grey too. TfL's map designers have therefore had to add a thin white dividing line either side of the tram zone, and they've made the gap above Hackbridge so wide it sends totally the wrong message.
Not wrong, but certainly peculiar, is the triangular Zone 5 island surrounding Sutton. Its presence means that Zone 4 gets to bend underneath Zone 5 whereas in real life it crosses to the north. Again the underlying issue is that Zone 4 and the tram zone are the same colour. The trouble with inflexible rules, however good the intention, is that they sometimes force you to find impractically contorted solutions.
Including zones on the tube map introduces all sorts of awkward constraints. Lines have to bend awkwardly and stations have to be irregularly spaced to fit them in. Removing zones would neutralise various issues. But zones are also important as a check on how much your journey is likely to cost, which may not be an issue you have but I'm one of those who find them invaluable.
To remove the white trenches and solve the Hackbridge issue requires the breaking of a rule.
I'm going to suggest shading the tram zone green rather than grey. A very light green, so as not to be too intrusive.
The green colour permits Zone 4 to nudge up against the tram zone, problem solved. It also allows me to kill off Triangular Sutton Island by placing Zone 5 underneath Zone 4 which is where it ought to be. I think it's hugely clearer, but remember I have broken a rule so it's probably not allowed.
In the meantime TfL have published a tube map which suggests journeys between Hackbridge and Mitcham cost more than they actually do. It is perhaps fortunate that the printed version isn't being released until next month.