I apparently didn’t have much to say about the old 5AT back in d93 (yes, the old 5AT had been sitting around for seven years, which is almost as long as the Kagurazaka), so I’ll start from the top.
Much like the ACE, the 5AT is an advanced steam locomotive that was developed and not built. The difference is that the 5AT is a much more recent design, and that the construction has only been recently shelved (obviously it could still be built – with a higher probability than the ACE). It seems to me that the 5AT was also much further along in development than the ACE ever was. There are a lot of detailed calculations and CAD models on the 5AT website.
All of my train models up until the ACE – from the 2004 K1 to the 2006 5MT (of which I only recently took good pics and only recently took apart in order to make the ACE) – were done by eyeballing reference photos and estimating where stuff went. In retrospect, that worked maybe somewhere between poorly and okay, but at the very least these rough models turned out much better than the fictional trains that came before.
This story starts a few months ago, even before I put down the frame of the ACE. Of all the legacy models I had in existence when I got back into Lego last year, the old 5AT was probably one of the better ones (which is why it’s the last to be replaced, I guess). Nonetheless, even at the time of construction I probably realized that there were some things that weren’t being modeled quite right (the most glaring thing being the lack of the curve above the cylinders), but overall I never thought I was that far off.
But then J and I started talking about doing things “right” with brick paper, and I think we were talking about how big various BBB wheels were supposed to be at 155mm to the plate height when we realized that the wheels on the old 5AT should have been much bigger. In fact, even the XL drivers that I am currently using are technically still a little small. Well, any and all of my believe in the accuracy of the 5AT model went away about there, but with the ACE project underway I wasn’t about to go and rebuilt it just yet (because I hate doing two things at once), so I didn’t.
Eventually the ACE got done to the point that I was just waiting for parts, so I borrowed the XL drivers I’d bought for J and started messing around. Since it was so small (relative to the ACE), I managed to “backdraw” (you can see the incomplete ACE tender in the background) almost the entire outline of the loco before filling it in with the production model. I kept the old version around as long as I could as a comparison, but eventually I needed to steal parts from deep within.
Same sort of deal for the tender:
As far as construction details go, there isn’t anything super amazing here. The chassis is just two “bogies” with a set of blind drivers leading the rear one. I’ve had my doubts about using blinds because I think they are ugly and increase rolling resistance in many configurations, but I was converted after doing some testing for J during which I found that the lack of a flange is much less noticeable at the size of the XL drivers and that the BFF configuration (even with drive rods) was quite smooth. The biggest source of friction in this chassis is actually in pivoting the rear bogie as the loco goes in and out of curves.
The body is mostly traditional studs-on-top construction with the exception of the greebles on the front bogie. I tried to minimizing the amount of 7-wide construction in order to conserve parts: similar to what I did in the Leader, the structural backbone of the locomotive is actually just a long block of 2xN bricks and the exterior kind of “hangs” off of that. Same sort of deal in the tender.
The boiler is technically a “121% volume” boiler from our friend Ben, but it isn’t really noticeable if you ask me. Just for the record, this 2013 model is a completely new model: it shares no similar assemblies with the 2006 model, even if I call it a “rebuild”.
The tender is actually my favorite part of this model. The spoked wheels really take away from the modernity of the locomotive (which, like the ACE, should have “Scullin” wheels) since they are a big part of the visual appearance. This doesn’t happen with the tender since the wheels are both smaller and covered (the highlight greeble), and I think the tender accordingly looks as sleek as it should be. I didn’t notice it until just now, but the surface is also 100% studless, which probably helps.
Anyway, the full Brickshelf gallery is here, and I think that’s all my comments on this.