well, I just can't get over it

I was surfing Twitter the other day when I came across this tweet:

Bassaleg : old rails make a decorative and effective reinforcement to the world's oldest railway viaduct still in use. https://t.co/6NM1M7VQZf

— Robert Humm & Co (@RHummBooks) March 21, 2021

I thought to myself, hang on, that looks vaguely familiar, and not only that but Bassaleg (pronounced, slightly unexpectedly, Baze-leg) is in Newport, or rather on the western outskirts of it over by junction 28 of the M4. I had a quick look on Google Maps and it turns out to be here, spanning the sensibly-named Viaduct Way as well as the River Ebbw on its way into central Newport. The reason it looked familiar is that I'd driven under it a few months earlier on my way to pick up something Hazel had bought online from someone who lived in the newish housing estate north of the viaduct in the little triangle enclosed by the railway and the river. I can't remember whether it was Viaduct Close or Viaduct View, but what I will say is: good luck getting a view of the viaduct from Viaduct View, because it ain't happening.

Anyway, you can see from the original tweet that a bold claim is being made here, specifically that the Bassaleg Viaduct is, and I quote: "the world's oldest railway viaduct still in use". Claims of this sort are a bit like claims made by distilleries to be the oldest, biggest, highest, northernmost, etc. etc., in that you have to dive down into the small print of the claim that's actually being made to discover the weaselly qualifications it's hedged about with to make it applicable to the specific thing you want to big up.

In this case "viaduct" and "in use" are the two bits that hide a bit of weasellery. One of the things it becomes necessary to consider here (if, of course, you're in the tiny proportion of people who actually give a shit) is: what's the difference between a bridge and a viaduct? Also: what does "in use" mean? Still connected to the rail network and carrying usable track? Actually traversed by trains on some measurable schedule? Carrying regular passenger traffic?

The stock answer to the bridge vs. viaduct question is: a viaduct is a bridge with multiple spans. The reason that this matters in this particular case is that Skerne Bridge in Darlington, opened in 1825 (a year before Bassaleg Viaduct), is also still in use, but is definitely a traditional old-school bridge, with a single span over the River Skerne. Skerne Bridge, as it happens, also fulfils the most exacting version of the "still in use" condition, as it carries passenger trains on the Tees Valley Line to Bishop Auckland and points north. Bassaleg Viaduct, on the other hand, last carried regular passenger traffic in 1962 and since then (occasional enthusiasts' specials aside) has only been in use by goods trains to and from Machen Quarry, and those seem to be very infrequent these days.

Have a look at this Wikipedia page and search for "oldest" and you'll see why these distinctions matter: Causey Arch in County Durham is the oldest surviving railway bridge in the world, built exactly 100 years before Bassaleg Viaduct, but these days only carries pedestrians, as does Laigh Milton Viaduct in Scotland, built in 1812 and also, confusingly, making the claim to being the oldest surviving railway bridge in the world. Adjust that claim to "viaduct" and they might get away with it. 

Another little Newport oddity can be seen if you look at the area surrounding Bassaleg Viaduct (it's circled in red on the map below):

You can see that the viaduct is on a spur off the main line (it's the passenger line up to Ebbw Vale) and that there is a station on that line called Pye Corner. What's odd about this is that, despite that being an unusual name, there are two places called Pye Corner in Newport, one (this one) to the west of the city, and one to the east, a little over four miles away as the crow flies, shown below.

I've no idea what "Pye" in this context is meant to convey or how it derives etymologically. What I can tell you is that there is a location of the same name in London which claims to be the point where the Great Fire ended in 1666, and which is marked by a monument comprising a plaque and a little fella known as The Golden Boy of Pye Corner.