First Real Scratchbuilding Project - S Scale Generic 4 Axle Tender

[Jake S.]

Hello all! I've been around for a while, but haven't posted in a long while due to having fallen out of the hobby. I have recently returned, and here I want to document the progress on my first real scratchbuilding project, which is an S scale 4 axle tender. It's not meant to complement any specific locomotive, as I don't own any locomotives in S scale yet, but the goal is to build something that would look nice behind a medium-sized locomotive, such as a 2-8-0, 2-8-2, 2-10-0, or what-have-you. I've also tried to plan for all of the considerations I'd need to think about when building a tender to complement an actual model, things such as speaker holes, ensuring there is adequate space for a speaker and decoder, as well as making sure that there is a way to route wires from the tender to the non-existent loco. I'm also striving for P:64 levels of realism. (or at least as close to them as I can get as a complete beginner) I'm not sure if I want to commit fully to P:64 in the long term, but I figure that since this project is basically going to be my entire engagement in the hobby for now, I might as well go all out. That being said, I'm still brand new, and have almost 100% overlooked something, so if you see anything whatsoever, feel free to tell me, as I'd appreciate the input immensely.

The tender is (very) loosely based off of that of an Illinois Central 2-8-0 I found in the Model Railroader Cyclopedia, and while the first few attempts followed that form more closely, this time I was much more willing to take my own liberties and make something myself, and I really only referenced the drawing for general proportions and such.

As of now I've made a model in Autodesk Fusion 360 as a reference to use when building, and to help wrap my head around how exactly everything will need to go together. Everything has been modeled as it would be constructed using available materials from Evergreen styrene, so all of the C-channels, I-beams, etc are all representative of actual available stock and will translate directly into construction. I followed very closely this article from the NASG about a tender Paul Washburn built, with the major difference being that my tender will be that of a coal-burner rather than an oil burner.

Pictures of the work so far:


A generic 3/4 view


Same as above, but from the bottom, giving a better view of the frame. Since I'm going for P:64, a well-modeled frame was important to me.


Rear 3/4 view showing the coupler pocket. The outside of the coupler pocket is scale-sized, but the inside is sized to accept a Kadee 802 or a Sergent EC64K. I'll be going with the Sergent for this project.


An image of just the frame. You can see that the buffer beam between the locomotive and tender is hollow. It is my hope that wiring between the locomotive and tender may be routed through this and hidden from sight.


A cross section showing the inside of the tender. Visible are the mounting and sound holes for a Soundtraxx 810078 40 x 28.5mm Oval Speaker.


And finally an exploded view of everything.

There will definitely be another computer model or three before any styrene is cut, so feel free to critique, as now is the time to make changes.

[Jake S.]

A quick update: I've begun work on the second draft of the tender. I was having an issue where the gap between the bottom of the frame and the top of the trucks was very large, about 7 scale inches, but I took some measurements and found that my frame was very high up compared most things I could find in my cyclopedias, so I lowered it by about 5", and made sure to cut out part of the end sill so that the coupler will stay at the correct height. That left just enough room for a 0.030" circular pad, which looks pretty much like what I saw in the one picture I could actually find of a locomotive tender's bolster. (Which was just a very grainy picture of D&RGW 497's tender wrecked on its side.) I've finished up the majority of the new frame, the only thing left being the box on the front end sill for the drawbars and the bumper for the locomotive. I also trimmed down the strike plate for the draft gear box quite significantly, and changed the rear end sill to have a simple, small rectangle around the draft gear box rather than the ridiculous looking trapezoid design. Again, if anyone has any input, I'm happy to listen. Some pictures:

(Please ignore the disgusting trucks. They are only there to serve as measurement references.)

[svedblen]

An impressive project! Will be fun to follow along.

I guess all your styrene cutting must be very exact and accurate. Any thoughts on how to achieve that?

[Jake S.]

That's a good question, and not an insignificant concern of mine. I'm still new at this, and in don't at all doubt that I will have to throw out parts that aren't up to snuff. However I've spent time looking at Gene's Proto:48 blog, and he seems to use a lot of jigs to ensure that the parts of his builds are constructed correctly. I will also likely wind up cutting parts slightly too large and filing them to fit. But that's what this build is about: the journey of figuring all of this out.

[svedblen]

I will also likely wind up cutting parts slightly too large and filing them to fit. But that's what this build is about: the journey of figuring all of this out.

That is probably a good idea. My experiance with a cutting tool like the Northwest Short Line Chopper is that the blade tend to bend when cutting styrene of any larger dimension, making it very hard to get a precise cut. And "large" in this case is not very large (1/8" or 3 millimeters).

[chessie system fan]

That's an excellent beginning!  However, I do see one glaring error.  The coal bunker widens out to the edge of the car. It's not narrow and straight like you have it.

It should look something like this:
____________________
L_/                     I                  I
     I                     I                  I
  _ I                     I                  I
I   \_________I________I

And the height of the front of the tender is usually dependent on the overhang of the cab.  So plan for that before cutting any styrene.

[Jake S.]

Indeed, this was something that was pointed out by a friend of mine, and it has been addressed now that I've started on the body of the current draft:



As for the height of the bottom sheet of the coal bunker, I don't yet own any S scale steamers for this to pair with, so I'm not concerned about it matching up perfectly. I did measure the deck height of a fair number of locomotives similar in size to what this would accompany, and all had their decks at about 6 feet from the rail head, so that is what I went with.

EDIT: Or if you mean the actual tippy-top of the coal bunker, it's a hair over 15 feet, which is definitely on the tall side, but not completely unheard of from what I can see. But the top of the slope sheet is another issue at nearly 17 feet from the railhead. Super no-good. AAR plate C limits the height to 15' 6." I've also discovered that the tank is too wide, by 4." Thankfully changing the height is as easy as editing a single number in my parameters, but unfortunately editing the tank width does not seem to want to play nice, and a good amount of work will have to be redone to accommodate that change. And to think I so very nearly went with a 10'6" wide tank instead of an 11' one. I may simply finish this draft and have it be a little to wide, and then make sure to use a 10'6" tank on the next draft. Thanks for pointing the height out - this is exactly the kind of stuff I'm looking to catch.

All that said, I did create a side-by-side-by-side of 3 different heights, starting with the current 9' tall tank, down to 8' and 7'. Personally I like the 8' tank the best, but the upper rounded part of the slope sheet will need to be either reduced in size or leaned back a bit as it's still just a little bit above the maximum height. But what are you guys' thoughts?