You get pretty good with simplified representations and other strategies when handling massive assemblies!

Steve Hunter

I strongly disagree with the latter part of that. If you are building a live steam locomotive and starting with an erecting drawing in my opinion actually building a 3D CAD model will save you lots of time as opposed to lengthening your project. I can knock out a cad model of simple parts in very little time, though I must admit that the latter steam casting drawings such as the type you will see on the T1 project and similar parts ordered from the suppliers can be a whole other story in terms of complexity. On the other hand it may take me 10 hours to machine a single part for my locomotive and and maybe I have two of them, well if you get to assembly time and the things don't fit and must be remade cause you messed something up the 30mins you saved modeling those parts in CAD really won't seem like much of a bargain!

In my case granted I was living in an apartment for some of the time but I built the 3D cad model and it was the best thing I could do. Here's a photo;

The plans offered by this manufacturer were terrible and loaded with parts from different locomotives, so the savings are huge. Having the 3D cad models has also allowed me to make changes to many of the parts to make them look more realistic. Your discussion about collaboration is an interesting one however. I have done a lot of work on my computer and it would seem like a shame to hog it amongst myself. I sure would love to find someone to trade and offload some of the design work with who was building the same locomotive.

Now for the harder part, my locomotive uses very simple parts in comparison to the final years of steam and those that existed in the superpower era. I have worked with some of those parts to convert them to 3D CAD and am presently volunteering to help convert some of the drawings for the T1 group. They can be a real challenge to work in. The old time draftsman really had unbelievable talents in some ways but were still human. Today those of us who work in the 3D CAD world are accustomed to parts that always resolve and geometry that always works. The computer won't let you build the 3D model if it doesn't work. On the other hand I have from time to time found geometries that just don't work on the old drawings. Oftentimes the projected views may not be 100% complete as the draftsman wouldn't bother to project a geometry if it was extra drawing time and they had already detailed it on one view. However sometimes just having that other view would be a huge help. Heck today we likely would put an isometric view on a print just to help show what was really happening. Those just didn't exist back in the day. I have a feeling that more often than not the pattern makers would have played somewhat of a role in fixing things that didn't resolve raiduses that didn't work etc... and the job would move on.

I realize this is somewhat of a ramble but my thoughts are to anyone building a steam locomotive of any size/scale build it in CAD first. It is till far less resources needed to fix problems on the computer than on the shop floor.

By the way, here's a fun one for example I did for a friend who will likely be offering it in 1.5" scale

If anyone out there wants to reproduce/needs a Hunt Spiller replacement bell for their Big Boy/Challenger and wants to get this 3D printed and cast please feel free to let me know.

Hi adammil1,

Although no longer a Live Steamer, Live Steam is the main place where steam locomotive production still lives. Smaller scale and not exactly the same as full sized, but Live Steamers do keep the steam design process alive.

I hope those who work on NEW steam (PRR T1, and several others) have not forgotten the experience of the Live Steamers. Might not by 100% useful to full size, but LS does design from the ground up in many cases and might be able to help out in some places.

Doug vV

This is the best argument for modeling as much of the locomotive as you can. No one really knows if the drawings are accurate or as built. It's good to know if a part is going to work or fit before money is spent to build it.

I also think I perceive a misunderstanding in this thread about the time and cost associated with 3D CAD. Solidworks, or at least my distributor, gives away a personal license for every every license my company purchases. Every engineer I know in real life has a copy of Solidworks on their home computer. There's not a part on a locomotive that I couldn't model on my laptop while sitting on my couch in my free time. I don't think the T1 trust have these misconceptions and are taking advantage of the fact that Solidworks is widely used and are either getting in kind donations of CAD work or someone within the group is just doing the CAD work in their spare time. The screenshot of the running gear the group posted could have been modeled in an afternoon, easily.

And that sort of thing will bite you on ADA. If you spec to ADA minimums, when your inspector checks as-built, you have a 50/50 chance of failing. And then you have to rip it out and do it over. If ADA says 1:12 ramp, build 1:13.