Though he lives in Birmingham, David Smith often works as a guard/signalman/controller on the Ffestiniog & Welsh Highland Railways in Snowdonia, North Wales.
Getting to know a few locals who worked on the railway and spoke Welsh as a first language, Smith started to feel bad that they had to swap to English to talk to him. Sometimes, passengers would ask questions in Welsh too. So Smith decided to start learning the language.
A few years down the line, and a small group of the railway workers occasionally meet up in London. Explains Smith, "We were on the Victoria line one evening on the way back from the pub, looking at the map in the train, and we started translating the various places into Welsh.
"We liked the sound of it and talked about doing the whole map. I had a couple of days at home where the weather was miserable, so I started translating the tube map."
Smith went through the etymology of each station (with a little help from Londonist), translating these into Welsh and putting it together into something that 'sounded' like a place.
"It was quite an interesting process, learning stuff in English as well as practicing Welsh," says Smith, "For instance Bethnal Green might be something along the lines of 'Happy Corner Green', which ended up as 'Maestrohapus' in Welsh."
A few places proved tricky. Harrow, for instance, means 'heathen temple'. "I kept searching and eventually came up with 'Cangell'," says Smith, "which means something along the lines of 'sanctuary'.
"Another issue was that there are an awful lot of place names in London ending in 'wood', 'Road' etc, so I had to try to avoid things being too repetitive."
He also decided that, where stations contain the names of people, to retain it (albeit put into the Welsh alphabet for pronunciation purposes), so Baker Street (named after William Baker) becomes 'Stryd Bacr' rather than the literal translation 'Stryd Pobydd'.
"One thing that really helped was having two of the friends, Lisa and Elen, who are both first-language Welsh speakers."
Smith points out that he's still very much a Welsh learner, so there may well be some slightly iffy language and/or typos on the map. He is also learning North Walian Welsh, which is different in places to South Walian Welsh.
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All images © David Smith, Elen Bradley-Roberts, Lisa Peters & Howie Russell