There's a very small gap between where the two panels meet on the engineer's side, you can see in the screenshot where the yellow striping of the RS3 behind is peeking through slightly. The same issue is a little more pronounced on the fireman's side, it runs much higher but is about the same width.

Up to you how much it actually matters. I spotted it out of the corner of my eye while running in 4k, but at smaller resolutions it definitely isn't as noticeable. There's a couple of holes in the rest of the model as well:


Under the engine room door affects both the PA and PB. An issue specific to the PB is a very large hole under what I presume to be the B end of the unit? If it helps for troubleshooting at all, it's the end without the fan.

Also found a couple of shading errors.

Window surrounds on engineer's and fireman's side should be smooth shaded. This issue goes all the way to the bevel at the center pillar.

This one's a twofer. The class light and numberboard surrounds presumably should be smooth shaded, and there's this odd error when rendering the numbers at an angle where there's this grey region that crops up. Having had a closer look, I think it might be down to how the numbers themselves are textured; as near as I can tell, it's a plane textured black with the TrainDecal shader, and then the numbers punch alpha holes through it. Because the sides of the numberboard box are textured the grey-black of the body rather than the white of the inside of the box, the decal renders as a different color when you look through it at another surface.

Four fixes I could suggest, although they each have some shortfalls:
1. Move the numbers further back. This might not have the intended visual appearance, and you might get z-fighting issues at a distance.
2. Paint half the sides of the box white. This wouldn't totally fix it as there's still a hard corner in there, but it would make it a much less noticeable issue.
3. Make the number textures white, and put them against a black background using a shader that renders more solidly.
4. Use a different shader entirely for the numbers. I'd caution against this, as TrainDecal is the only one that supports full 8-bit alpha transparency.
Overall the PA is a decent model, although evidently a few things were overlooked in presumably the export process from the modelling software of choice to TS. A lot of these seem to be related to things that were changed from the Unity render that was shown off a while back, like the numberboards and the PB. Luckily, with the (possible) exception of the numberboard box thing, none of these should be a terribly difficult fix; most of them should hopefully just be a right click, 'Shade Smooth', and possibly an edge split to set straight, or otherwise adding an extra few faces and giving them the right space on the UV.
Matt J.