Well…
I got an email that said my 80th Anniversary Mallard model had shipped. Obviously, that got me excited, which made me go browse other railway models on the web.
That's when I first noticed that A4s — both models and in real life — are sometimes seen with an external pipe running along the side, smokebox to cab, just below the hand rail. But other times, in other photos, that was missing.
Hornby's photos of their 80th Anniversary model show Mallard with the pipe. And in some photos of the real engine, both present and past, Mallard does have it. But in other photos that can be found online, it doesn't. Which made me question whether this model was modelled after Mallard at a specific time period under a specific configuration, and whether that's historically accurate and appropriate for a model made to commemorate a specific event in 1938.
Having no idea what that was about, I started looking around. It's not uncommon for engines to go through minor and major mechanical modifications throughout their working lives, and the A4 was no exception. So I thought the pipe might've been a change they made after the initial design and build.
But I couldn't nail down any rhyme or reason as to when that supposed modification was first applied. There are photos and illustrations of the same engine at different time periods showing it both with and without the pipe, which didn't help. The pipe can be seen on an illustrated poster advertising the Silver Jubilee service, but missing in some of the publicity photos of the original batch of silver engines. It can be seen before, during, and after the war. It might be shown in photos taken when A4s were still running mainline service, as well as after preservation. Or it might not.
I couldn't find any text online about that pipe either. Thinking someone else must've wondered about this before as well, I tried a whole host of (vague) keywords, but there didn't seem to be anything.
Packaging for models of the A4 sometimes show the pipe, but it's not always shown on the actual product when people take and share photos of them online. Maybe it was an error in the packaging, and the model wasn't meant to have that detail. But then I also see photos where the pipe is missing on supposedly high‐detail models.
And then, I saw photos of A4s from the same event on the Science Museum website. I finally noticed it, and made myself feel silly: that pipe is only on one side of the engine. Specifically the right side, if you're looking at the engine from the front. It was never on the other side, and it's an asymmetric feature of the A4.
That was a few hours going around in circles chasing nothing…
I wonder what that pipe does, and why it couldn't be inside the casing.
