Spring Rigging... how much does that axlebox move?

[locodan5416]

Hi,

Lately I've been fiddling on AutoCAD doing a usra 2-8-2 in 3/4" scale. After starting out with the boiler and cylinders, now i'm at the frame. So here is my question... how much do you think that a axlebox will need to move in 3/4" scale on a elevated track? My guess is no more than +/- .125"

Everything I've seen involving spring rigging isn't useful at all. in our scales of choice, the equalization is more important then the spring rigging.

[pockets]

Dan, For a soft, smooth, even supple suspension, what is needed is the softest spring that will cary the weight at the desired ride height. A good starting point is to carry about 80% of engine weight on the drivers. This makes spring rates very important. Most engines are WAY over sprung.

We did a whole thing on this, over at Railfan.net.

Greg B.

[locodan5416]

I mean how much does an axlebox really need to travel. I think it is more important for the axlebox to go down then go up. going down would be like a low connection, but the engine would start going up from the lead truck if the track rose

[dolfa]

Hi,
here I have a book on building Maisie in 3/4 gauge by LBSC.
The slot is 1 3/4 long and the axle box is 1 1/4 long .Looks
like there is 1/4 of an inch play in both directions.

[GoldenSpike53]

Hey, Dan, good topic and good question.

I think you are correct that equalization is more important than springing, especially on a model. In fact, Gene Allen, in his later designs, went to faux springs (cast aluminum) in the equalization system because no one is riding on the locomotive so the "comfort" of the springs is not needed.

As to axle box travel, you have to remember that, in an equalization system, as one axle goes down the other goes up by an equal amount. Therefore, both directions should be equally important. When you look at how the equalization system works, this will become pretty apparent.

Good luck!

Dale Dennis

[locodan5416]

I didn't know about the allen change. My dad is anxioussly awaiting our last box of castings for the mogul... i think he might be setting a record building the engine? we started in the end of october. i need to go out and get the digital picture for the forums.

Dale, your building a Allen Loco right? What sort of paint are you going with? we're black oxiding the frames, and probalby going up to sherwin williams soon for paint advise on the pilot beam, wheels, etc.

about the mikado i'm drawing... i'm really tempted to use a convient piece of 3/8" thick 1018 low carbon precision ground flat stock, and go from there. i'm not really concerned about the springing. i am going to do a kozo though and start with the tender... who knows i might make it into a series?

[GoldenSpike53]

Hi, Dan.

Yes, I'm building the Allen Consolidation 2-8-0, mostly because it has Baker valve gear instead of Stephenson. (I prefer outside valve gear. ;D There's nothing wrong with Stephenson in terms of operation, and many people like it, so don't get me wrong.....)

I also run the AllenLocos group on Yahoo! for those of us building Allen Models engines.

I've talked to a number of people at our club here who agree that having working springs on a model loco is overkill, and working out the equalization with real springs, having to account for the give, probably makes it more complicated than it needs to be.

I haven't gotten to the point of painting anything yet. I have a friend who runs an automotive paint shop, and he has offered to do the painting for me and I may take him up on that! But the frame I agree should be painted black, and a powerder coating probably doesn't hurt. But I haven't researched that much as yet, so can't really give you a good answer. Sorry. (Hopefully someone else will chime in on that subject....)

Dale