James, Great to hear about the possibility. What mechanism would you plan to use under your shell? By any chance would it be the Atlas B40-8 mech with the Atlas C628/C630 trucks? If so, my PBase album about my (slow) RSD-15 build, has a bunch of photos of this mechanism/truck combination. Feel free to look that info over and let me know if there's any questions I could answer. The real value of this particular mechanism/truck combination is that the truck spacing is very nearly dead-on, within 2% of what it exactly should be. Below, in order to document some N scale research that may be of interest to some, I discuss a bit more about that nearly invisible 2%
For what it's worth, here's what I posted in Feb 2013 over on another N scale RSD-15 thread, in post #42: http://www.trainboard.com/grapevine/showthread.php?83501-Looking-for-RSD15-owners/page5 Bottom line: ** The Atlas B40-8 mechanism with Atlas C628 trucks gives a very nearly accurate RSD-15 wheelbase ** Accurate within 10 scale inches (only off by 2%) http://www.pbase.com/atsf_arizona/image/148672757 Thx to many, including Alwyn out of Australia, for helping with this research. Our rivet counting conscience can now go and build massive numbers of RSD-15's in peace, using this combination of mechanism and trucks. Would be happy to hear comments/suggestions on other mechanism combo(s) that might be used under a 3D printed RSD-15 shell. ---------------------------------- For those who care, below I've included the calculation, combining data from the following sources: * Data in the HOSAM websites for the Alco Roadswitcher dimensions: http://www.hosam.com/alco/rsdim.html * Same website, GE B40-8 truck center to center wheelbase dimensions: http://www.hosam.com/ge/gewhb.html * RSD-15 plans from Feb 1988 Mainline Modeler, article by Robert Hundman and John Nelsen -------------------------------- Here's the computation. By looking at the RSD-15 plans: * The Alco RSD-15 plans show center to center of Alco trimount trucks TRUCK BOLSTERS is 43'-06" (confirming Note 2 in the HOSAM table). * However, the plans also CLARIFY that distance, by identifying the truck bolster location is 1' 10" OUTBOARD of the center axle (the plans/pictures worth 1000 words, the plans clarify what the HOSAM table was trying to say) * In other words, the Alco trimount truck's CENTER AXLE is therefore 1'-10" INBOARD of the TRUCK BOLSTER * Remembering that the gear tower of the N scale Atlas C628 trucks is directly over the center axle..... * We therefore need to calculate the prototype RSD-15's center-axle to center-axle distance * To do that, we calculate: (RSD-15 TRUCK BOLSTER distance) - (1' 10" front truck) - (1' 10" rear truck) * Plugging in the numbers: (43' 6") - (1' 10") - (1' 10") = * And that equals 39' 10" is the exactly correct RSD-15 distance center-axle to center-axle * I used my N scale-ruler to measure my B40-8 chassis with C628 trucks * From an eyeball / caliper / scale ruler standpoint, my eyeballs sure looks like it measures almost exactly 39' 10" spot on that distance * The fact that the Atlas B40-8 mech + Atlas C628 trucks gives a distance of 39', i.e. 10 scale inches short...... I can hardly see it * Certainly, for most people including me, I can't see an N scale 10" difference - especially given our modeling compromises and manufacturing tolerances for a 1:160 model * For reference, N scale 10" equals .0625 real inches, which is approximately the diameter of a #52 drill * (a #52 drill is slightly larger than the #56 clearance drill in the MicroTrains tap/drill set. ) * (i.e. the error in RSD-15 truck spacing we're talking about is same as diameter of mounting hole in MicroTrains 1015 coupler box) So, next I investigated further, why the wheelbase of the Atlas B40-8 mechanism along with the Atlas C628 trucks, gives an almost dead-on accurate wheelbase. --------------------------------- To do that, I researched the GE B40-8 center-of-truck to center-of-truck distance, to compare this to the Alco 39' 10" distance * We see from: http://www.hosam.com/ge/gewhb.html * That the GE Dash 8-40 truck center-center distance is 39' 0" * i.e. only 10" off from the Alco RSD-15 center-axle-center-axle spacing of 39' 10" ---------------------------------- * We can see from following photos, the B40-8 truck gear is centered on the 39' mark per B40-8 dimensions * We can see the C628's gear tower is over the center axle, therefore when I swap the Atlas C628 trucks into the B40-8 mechanism... the C628 truck center axles are thus spaced....... 39' feet apart (pretty close the the 39' 10" that would be exactly accurate) http://www.pbase.com/atsf_arizona/image/148672764 ----------------------------------- What this means is the Atlas B40-8 mechanism locates the C628 gear towers and center axles, a scale 39' apart Which is within 10" of what a perfect scale gear tower location of the Atlas C628/C630 trucks should be for an RSD-15 (i.e. 39' scale distance on the model vs. the correct 39' 10" on the prototype.... the error is 2%) --------------------------------- This happy circumstance happens because the Atlas N scale C628 truck gear tower is centered over the middle axle, NOT over the actual middle of the truck. All this is why the Atlas N scale B40-8 mechanism using the Atlas C628/C630 trucks, turns out to be almost perfect spot on, within 2% match, for correct RSD-15 truck spacing. Credit is due to Jim Bence, president of the San Diego Society of N Scale club at Balboa Park in San Diego, for first posting way back about 2004, that he'd discovered this combo of B40-8 mech and Atlas C628 trucks, would work, and he used that combo under his N scale Southern Pacific RSD-15 he'd built (using Model Power RSD-15 shell). Hope this may be of use for future reference for a possible 3D printed RSD-15 shell . Respectfully submitted,
I'm not sure how good the original Roco/MP shell lines up with reality, but the expensive part of such a project, i.e. doing the artwork and etched brass handrails and details, is a 'win-win' whether you go retro and use the old shell, or if somebody prints a new one in RP. Either way, the etched details are necessary, and if you're careful on design, would work for both. Just follow my lead and make drilling templates part of the design. Think about that part, Dave C. & Jim. Nudge. I'm not doing it, you guys can fight it out.
Hey all I got a response back from BLI. Here is there email. Looks like they are working on it but might take a little time. Hi Kevin, We'd like to build an RSD15, but we're still working on fitting our N scale circuit board and a speaker inside the narrow body of the RSD15. This is the hold-up with a lot of diesels and small steams that we'd like to model in N scale. Let me know what else you'd like to see in N scale. Thanks! Sincerely, Matt Williamson Broadway Limited Imports Sent from my iPhone using Tapatalk - now Free
That's great but BLI stuff is a bit out of my price range and I don't need/use all the fancy do-dads BLI crams into their units... Maybe Atlas will jump into the fray and bring something less expensive online.
Hi, sorry I missed your post. I'm still thinking about it, as I have several other projects to finish up first. However doing the 'Atlas B40-8 mech with the Atlas C628/C630 trucks' is a good idea and I will investigate that a bit further. Are the trucks available as spare parts? I ask because it is a shame to sacrifice two locos to build one. I will keep it ticking over in the background while I finish up my RT624, C-855 and turbines that will be out soon. Once I get past the NMRA (BR) convention in a few weeks I should able to pick up the drawing pace a bit. -James
I'd recommend that you have an offline discussion with Paul Graf on stuff like this. Sometimes they are very limited on specific parts and have no idea that somebody is considering a project that has the potential of draining them on specific stuff, or why. If they know it is coming, they can sometimes adjust part quantities from China a tad.
Sounds like the big issue boils down to fitting a speaker inside the loco and whatever circuitry is need for sound. Certainly the issue of a dual mode decoder to operate on DC or DCC is a non issue in that there are a number of both small steam and diesels out there that are dual mode decoder equipped from the factory. Drawback I see is the fact that if one starts removing metal from the frame to accommodate a speaker with the current light metals being used you end up with something with less tractive effort. That is unless one casts the frame in Tungsten maybe. Option I would choose is to offer two versions to the modeler. Sound or no sound, but both dual mode decoder equipped. I would do only one frame but simply have a cut out in the frame for the speaker that would have a simple weight filler in place of the speaker for folks that don't want sound but want the increased weight for performance. I would then offer the sound package as a later add on for folks that later decide to go the sound route. In short two basic options of with or without sound for the same road names and a third option of a simple drop in speaker and board package for those that later want to convert.
To me, it's one thing to put sound in steam... but to hold up something like this for X years due to that on locomotives that, in all likelihood, are going to be MU'd, well, I dunno. I want it to pull. I won't hold it against them if there's a hole on the frame I can fill with weight, but I'd just as soon not have to scrap an expensive board to do it. After test-running the PA on my layout, I was totally turned off on their product. It derailed constantly and stalled, and required absurdly clean track, and the static came into the sound system. Looked great sitting still though. As usual, Mark's commentary is right on.... http://www.spookshow.net/loco/blipa.html For me, if it derailed more than a Hallmark 4-8-4, it's got a distinct problem, and it appeared to me to be lack of lateral flexibility in the trucks and the frame. The wheelbase on the RSD-15 trucks is a little shorter, but it's in the category of 'I'd never ever preorder it'.
Personally I'd take them without sound if that's what it takes but Intermountain and Bachmann are bringing out hood units with sound and Atlas are even doing an Alco switcher with factory sound. To me this is another one of those 'we can't do that yet' excuses that has no credibility.
For one-third the price of the feature-laden, performance-challenged BLI model I'll take a Kato PA instead.
So how did a thread asking about and wanting companies building an RSD15 to let's bash those said companies? I know that some manufacturers may bebetter than others, butthere is no need to drag them through the mud. I contacted one out of many manufacturers and they were kind enough to respond. I don't see any one else doing that. I would prefer to see the responses from different manufacturers as to why they haven't built acertain model or if it is in the plans rather than see post after post degrading different products.
Hi, James, Randgust's suggestion to have offline discussion with Paul Graf of Atlas sounds like a really good idea, re: Atlas making some extra C628/C630 trucks as spare parts. Today, Atlas B40-8 mechanisms are easy to come by on that auction site. However, Atlas C628/C630 trucks as spare parts are out of stock at Atlas, as far as I can tell, so that's a problem. I bought up enough trucks off that auction site back in Jan 2013 to do three RSD-15s back, but haven't seen any spare parts C628/C630 trucks, anywhere, since. That's why Randgust's suggestion is a good idea. Atlas has another run of the C628's coming very soon in 4Q14 ( http://www.atlasrr.com/NLoco/nc628b.htm and http://www.atlasrr.com/ordership.htm ), so *right now* would be the time to reach out to Paul Graf and see if running additional C628/C630 trucks would be possible. How many people out there reading this thread, would be interested in buying some additional C628/C630 Atlas trucks for this RSD-15 kit bash?
My BLI PAs run much better than my Kato PAs. I don't have any derailment problems even going threw medium yard turnouts. My units didn't need the traction tires so they were replaced. The DCC decoders are IMO really great in sensing the pull of the loco and increasing or decreasing the sound accordingly. Also BLI has been improving there design with every release the latest has the same type of truck pickup as the Kato, except the BLI uses wires from the pickups to the decoder.
When I posted my commentary in post #25 yesterday it was no way meant as a bash of any particular manufacturer or their products rather it got down to how a manufacturer could possibly bring this product to market and offer some options to the buying public. And it certainly wasn't a license or an open invitation to start a bash of their products by any means. In that post I did suggest how the product could be brought to market and save tooling costs for both sound and non sound versions by the use of a common chassis frame with a simple weight insert for the non sound models. Comparing steam and carbody type diesels to a body like the RSD is wrong as far as having the room for a speaker. Simply put with steam you have the tender for space for board and speaker and in a carbody diesel there is a considerably larger chunk of metal that can be milled to accept those without seriously affecting the chassis weight enough to reduce tractive effort. The issue seems to be most likely the size of the speaker needed for decent sound for those folks who want a sound version and being able to maintain a fairly good tractive effort. That may lay in the use of the metal I suggested for a frame or chassis. No way should the commentary I posted be taken as a license to bash a particular manufacturer and since I own none of their products I don't even remotely feel I have the right to comment on that nor did I, or invite anyone to. Instead I offered my ideas of how to get the product to market and be able to satisfy the majority of modelers no matter which manufacturer does it.
John's got the message. And I got that message from Paul myself, anything but a 'no', more like 'next time, give us a clue and we'll up the parts order quantity' if you have some kind of Atlas-derived special custom product going on for something like Shapeways build or better that needs their parts. If a build takes a specific Atlas product to accomplish (like the B40) as the core, he can be pretty cooperative! RSD15's were hogs - 1959, 2400hp. Lasted on ATSF until the mid-70's. Those railroads that ordered them tended to MU pile them on heavy trains. So if you're modeling them, you're usually talking about more than one, and even if it is one, it's generally MU'd with something else - ATSF had them in the general pool to the bitter end. The 'truly great show' of RSD15's on ATSF was the period of time they were assigned on the York Canyon unit coal train - 6 on the front and 4 mid-train helpers, for 10 total on 90 loads west, and all 10 on the front for eastbound empties. For me, 4 on 30 cars is as close as I can get. A 'single' RSD15 on a train? Other than a work train, I'm not sure I've ever seen it. It's not a circus show pony, it's a draft horse in a team. EDIT: here ya go: http://www.railpictures.net/viewphoto.php?id=457019&nseq=4 And the congregational response: "HOLY #@@!$' which is completely appropriate. And by '72, the 'shine was off' http://www.railpictures.net/viewphoto.php?id=144115&nseq=17 Notice the oil leaks across the catwalks of all of them, down the yellow side sill, and the comparison of fresh warbonnet blue against weathered blue. They just need to look good, run better and be affordable. If they want sound, just leave space. I'll fill mine with lead. I really don't want to pay extra for that feature, make it board replacement. I'd wish Kato, hope Atlas or Intermountain, accept Bachmann, and sigh BLI to make these to current standards. That BLI response previously posted still indicates to me that it's 'sound over substance', and in my mind that's what also crippled the first release of the PA and makes me still suspicious of anything they release now without seeing it perform first on a real layout. It's nice to push the envelope, but there still better be something in it. And with BLI actively tinkering, probably everybody else (but Bachmann!) is hanging back. While it can be said to be unfair to judge manufacturers pre-release, I'll challenge that, particularly when there's confirmation that they're still working on it. I've seen some neat stuff happen before final production decisions, and this is the time to speak up instead of AFTER the container leaves China. My existing fleet runs well, but like most of the stuff on my layout, I have relatively low emotional attachment if something better comes along and WORKS. Wallets are standing by.
When everyone orders parts from Atlas to rebuild your old RSD15's be sure to tell them what you want them for, that might get across to them how desirable the loco is.
Good discussion, all. James Norris, I realized I'd better point out what sort of Atlas B40-8 mechanism modifications (i.e. metal removal) I had to do to get the Mehano/Model Power RSD-15 shell to fit. The amount of metal removal is a bit significant..... and I'm not sure if an unmodified Atlas B40-8 mech is going to be able to fit under a properly dimensioned 3D printed RSD-15 shell. Maybe someone who has plans of the B40-8 can can compare the hood length dimensions with that of the RSD-15 (email me if you need a copy of plans for RSD-15, I'll respond when I can as I'm out of town next few days). Here's four photos showing how much metal I had to take off the Atlas B40-8 mechanism. It's worthwhile that all of us considering this kitbash know up front that the amount of metal removal will be a bit significant. Comments? Anyone else doing this with additional info that I've missed? Thx, hope this helps.
John, have you ever weighed yours? I'm curious how it comes out compared to the Atlas C-628/C630, and also, if your conclusion was that there was any space left in there. I don't think that's all that much material removal compared to what I've done. The catch is that if you're going this way with a Shapeways product, you've got to figure out how you're going to incorporate instructions with photos and a guide as clear as what John supplies. To do it right, you really have to strip the mechanism components out of the frames and clearly identify orientation of everything - bearing blocks, worms, universals, motors - and make sure you can reassemble everything the exact way it comes out. I mark orientation on everything with scratches and arrows. Grind or file the frames, and wash or clean them to get rid off all the metal dust, then dry them and reassemble them. Just don't ever try grinding on assembled mechanisms!
