Anyway, there were two sections of the Piccadilly Line I needed to visit, and I did them both during one Saturday afternoon (and evening, as it invariably became).
This branch, which curves round from Acton Town to head northwards towards a rendezvous with the Metropolitan, represents another uninterrupted of Charles Holden-inspired stations, save for North Ealing which - as you'll see - stands out by virtue of resembling someone's house.
It's not a very well-served branch. It took me twice as long to travel this stretch as it did the Acton Town to Heathrow route (taking into account my need to get off at every single station, take photos, then wait for the next train). What the service is to frequency the stations are to hospitality. Despite their impressive designs, none of them were very welcoming. Then again, that could have been because they were mostly deserted, it was getting dark, and this was the middle of February.
There's been a station at Ealing Common since 1879, but Holden's version, like all of them in this part of London, opened in the early 1930s. Originally the District Line passed this way, in its previous guise as the Metropolitan District Railway. When the Piccadilly was extended to run west of Hammersmith, Ealing Common changed sides and marked the point (as it still does) where the two lines diverge.
It is, as ever, an imaginative creation, boasting the requisite Holden talking point: in this instance, a hexagonal roof. There also seemed to be the now familiar battery of small businesses skulking in side rooms, such as a taxi cab firm, estate agent or barber.
Actually, North Ealing looks more like a church hall than someone's house, but the incongruity of its design compared to its purpose remains. There's a cosy feel to the place nonetheless, not borne out by its platforms which stretch for miles and are barely welcoming.
When this bit of the line was built at the turn of the last century, a station was opened specifically - and temporarily - purely to serve the Royal Agricultural Society's recently opened Park Royal show grounds.
This sort of thing doesn't happen anymore. Stations are built to last, permanence is considered a premium, and there's neither the time nor money to waste on frippery that will have a short shelf life. I think this is a shame. Imagine the pleasure to be had in first discovering, then using, a station only erected for three months. Well, I'd find it a pleasure.
The main station at Park Royal still stands, and is a dazzling edifice. When the light starts to fade and evening creeps in, Underground stations turn into beacons of solace and safety. A lot of this is undoubtedly due to the way they are lit inside, which in turn is thanks to their overall design. Park Royal draws you towards itself like a well-tended hearth.
The onset of dusk doesn't always make for valuable photography. I had trouble at Alperton, where - by the time I eventually arrived - it was now almost pitch black.
This station was originally called Perivale Alperton, about as suburban and domiciled a name you're likely to get. Holden's building is once again giant-like in both size and ambition. In fact it's huge. It dominates the surroundings like an airport terminal.
Sudbury Town's lack of decent outside lighting rendered the chance of a decent photo almost negligble. I don't know if you can actually see anything here:
That is Sudbury Town station, I can assure you. The interior lighting did, at least, make for a rather dramatic wall of yellow, looming out of the murkiness.
For further proof, here's a shot of the platform:
The shot of Sudbury Hill below is almost two years old, and is another one taken during my circumnavigation of London on foot. I doubt, if I'd been here in the dark, I would have been able to capture anything on camera:
Finally, South Harrow and another station benefiting from a warm illuminated interior. Although this belied the mood of the place, which was grim and combustible. Saturday night was beginning, and Harrow's hordes were roaming. I got out of here as quickly as I could.
North of this point the Piccadilly meets the Metropolitan at Rayners Lane and runs in tandem all the way to Uxbridge: a section of the Undergrond I have already covered.
There was still unfinished business, however: that stump of the line that sprawls south westwards towards the sprawl of a terminus that is Heathrow airport.