Monday, September 24, 2012

Uncouple Anywhere 02

Made some good progress on the wagons this weekend.  Although I was pretty far along before, things were a bit over designed on the swing down version.  I moved the fulcrum and actuator and simplified the over all design.  Things are now reliable and repeatable.  In anticipation of car bodies, I went ahead and made the decals for the gondola sides.

Lionel Strang and I had an exchange on the Model Rail Radio recording the other day, in which I mentioned Canadian snow, and he responded by citing the salt in Utah. .  . This was enough to make Lionel the purveyor of my future salt works.

A lot of the work went into refining the pick up scheme.  I ended up going with Bachmann trucks.  The wheel backs are flat, and the frames are stiff.  Although there are more detailed side frames out there, the power pick up on fiddly side frames was just too unpredictable.  For this scheme to work things need to be bullet proof.  The spiral wind of phosphor bronze worked great, and with a little neolube on board, things are not too bright.  I only wish I figured that out before I custom cut dozens of folded flat wipers.  Oh well. . .

Wagon chassis #'s 301 and 307 are destined for actual car bodies.  Made a shot at cutting those last night, but did not get far enough to assemble.  Time for a breath.  I am going to customize the servo boards, but only when the wagon is closer to final assembly.

Design work continues on the vertical drop coupler, and a flat car design.  Waiting for some servo board kits, which I can bash a bit more easily. . . . looking forward to the time when I can put the soldering iron to rest though.  Getting car bodies painted will be good.


Sunday, September 16, 2012

Uncouple Anywhere 01

I did more work on a new version of the traverser (cad and engineering), but such things are boring when compared to wagons that can be uncoupled remotely anyplace on the layout.  The formula is simple, each wagon gets a servo decoder and a servo powered draft gear box to change the position of a coupler.  Temporarily dropping the coupler allows the car to be set out anywhere on the layout--regardless of what it is coupled to.  The evil plan?  Equip darn near every wagon on the road. . . cue evil laughter. . ."muahahahahaha".  Kadee glad hands tremble in fear, "no, not the wire cutter, nooooooooo!"  Seriously, this is one advantage of a small railroad--not too many cars to build in the first place, so each can be a tad more sophisticated.

The video above is of the first prototype: a tad rough, mainly because a wood grain pattern I etched into the floor caused a warp in the thin acrylic.  The pattern is fine in a thicker material, but I needed to downsize. . . I used this model to determine the minimum tolerances, and to experiment with clearances.  The brass was all scavenged from the scrap bin.

Mess of servos. . . small, smaller, smallest!
The workbench is covered with a mess of servos.  There are a couple 6v servos that are downright tiny, but the smallest is a linear 4 volt.  The plan is to assign the largest practical servo to each car type, as you get smaller you loose a little power, and the smallest will require voltage step down via rectifier diodes.  Larger servo's are cheaper to boot.  Servo prices range from as little as a few bucks a piece all the way to twenty smackers, needless to say, evil plans hinge on keeping the twenty smacker servos to a minimum.

Boxcar variant (straight drop), with decoder in background)
I have settled on using Tam Valley Depot's Servo Singlet as the "decoder" for the moment.  It's available in a semi kit form that will make re-configuring it easy.  The bulk of the singlet is in the connectors: if you removed the connectors, and flipped the switches, it can get downright tiny.  Depending on the car, I am planning to equip it with one or two servos, each servo requires a singlet.  In some cases, I am planning on pairing small cars.  Ideally, each singlet address will be the unique car number of the car.  As in the video, the plan is to have a red diode light when the coupler is dropped, so there is a clear indication of a dropped coupler, beyond the coupler itself. 
The straight drop version, cheap servo and a slider without play--very precise.
I have been working with two variants: a straight drop, and a hinged drop.  I like the straight better, even though I started with the hinged.  I figured that I would work both out, and then design the car fleet.  My first designs are based on a frame I had already been building to replace the frame in the ON30 IMA Kits I had.  In the course of trying to re-work the kit, I ended up designing an entirely new car and underframe, and the kits essentially were abandoned (save for the detail parts).  Nothing like building something to figure out what you really want to build. . .

Here is the first prototype, with the previous, non-servo version of the frame.

I'm not the first person to do this of course, there are some folks manufacturing HO box cars with this capability (via solenoid actuated coupler, not a drop coupler as I have it), and there are some European modellers using the Uhlenbrock Digital Servo (do your searches in German).  I think the key to making it fun is the evil part of the plan: enough wagons that you don't have to think about where, when, and how you uncouple. . . you just do it.

The new cut file, arranged to avoid warping!
The first two. . . cut just before the sheep busted out and I had to go fix a fence.

The detail parts arrived fast, thanks to the good service of Valley Model Trains.

Monday, September 3, 2012

Traverser 01

Much of the weekend was occupied by building a traverser for what might be the end of the line.  I cleared enough out of the store room to prop it in place for some ergonomic testing. . .

More on the construction in a moment, first, some explanation is in order.  Although the Virgin and Lost Shore began with a dozen scenes, when it comes down to it there are really only a handful that I feel are "must build".  The rest make sense , but I don't know if I want to commit to them.  Thankfully, I am working in modules, and these sorts of expansions and contractions of scope can be easily contended with. 
The plan above will get me where I want to go in a realistic time frame, and, there is nothing stopping me from re-configuring pieces down the road if I so choose.  The fact that I only have two more turnouts to build is an added plus.  The minimal design is both an aesthetic choice and an operational one.  More on that another time.  For now, lets get back to the traverser. . . 

I began with the tightest ball bearing slides I could find.  Bad news, even "tight" drawer slides are way to sloppy, and the initial idea of having a single ball detent in the middle of the table, with an indexed aluminum rack was a failure.  The table simply wagged to much side to side.  It was workable, but not good enough.

The aluminum also brutalized the ball detent, and its movement became progressively coarse.  One nice thing about the design of the detent is that the little gizmo is threaded, and in the installed position, could be easily adjusted for tension.  That was a feature to keep.

Plan "B" replaced the single aluminum rack with two perfectly identical acrylic racks and stereo ball detents, one for each track end. Fortunately, I remembered that I had two more ball detents on hand that I had removed from a client's home. . . so I was still in business.

The acrylic rack worked much more smoothly, and although I originally feared having dueling indexes, this proved to be the best solution for keeping things aligned.  My desire is to have loco parking beyond the traverser, so my locos are not land locked, and so I can keep a smaller stable of ponies.

Over all, it works well--and with the double detent, indexes consistently.  Although well enough to be reliable, I am thinking about making another crack at it--either with plastic guides made from HDPE, or with longer drawer slides (to counter racking)--there is good, but considering how important it is to the entire fun of the layout, I would love for it to work beyond perfectly.  I can always re-use the portions of this module base for another layout section.

I did not spend all my free time on the traverser . . . I managed to rough in some foam scenery base on the left side of the Virgin Railhead.  I have some structures planning to do, but I made some good progress.  The foam is held in place with hot glue, and some screws with fender washers.  As I intend to move the module inside and out for photography, I want to be sure that it won't "pop".  The terraced effect of the foam reflects the leveling of the land for flood irrigation.  I have exaggerated some of the vertical elevation for compositional reasons.  

I also managed to get going on some of my ON30 IMA kits, assembled trucks and couplers, and started work on some laser cut replacement frames.  I am sticking with the stock Bachmann coupler height (HO)--so, I need to do some work to get my cars to ride correctly.  This will be an issue with the passenger cars, but I am fast coming to the conclusion that I will need to scratch build those anyway. . . .

This acrylic piece is going to be the lower half of the frame, the notches hold the draft gear boxes.  I am sizing my work to fit Dave Mason's box car kit as it is already designed, and to use everything in the kit except the bolsters and frame.

All in all, made some progress this weekend.  It feels good to have a few balls in the air--always something to work on.