Author Topic: Taking the Plunge on Turnout Construction  (Read 5512 times)

0 Members and 1 Guest are viewing this topic.

Sokramiketes

  • Crew
  • *
  • Posts: 4955
  • Better modeling through peer pressure...
  • Respect: +1480
    • Modutrak
Re: Taking the Plunge on Turnout Construction
« Reply #30 on: July 12, 2013, 02:24:29 PM »
0
I haven't mastered the resistance soldering for much else, but a tweezer handpiece for laying track is the best thing ever.  It's exactly for the reason Bob mentioned... being able to separately control the heat from the holding.  Rail stays put until the joint is hard.  And the heat is localized. 

I'll use a regular 25W or 12W iron for everything else from electronics to brass models... but the resistance station is where it's at for track.

DKS

  • The Pitt
  • Crew
  • *
  • Posts: 13424
  • Respect: +7026
Re: Taking the Plunge on Turnout Construction
« Reply #31 on: July 12, 2013, 02:59:52 PM »
0
And yes, it IS all it's cracked up to be.

In your opinion. I have had different experiences. But I suppose they don't count.

GaryHinshaw

  • Global Moderator
  • Crew
  • *
  • Posts: 6332
  • Respect: +1856
Re: Taking the Plunge on Turnout Construction
« Reply #32 on: July 12, 2013, 04:14:23 PM »
0
As to hinged points... I've had good success drilling holes up through the base of the point rails at the hinge end, and silver-soldering pieces of steel wire into the holes. Then I drilled holes through the ties in the turnout, inserted the wires, and bent them on the underside of the switch to secure them. The wires also provided spring tension to the points so they didn't need to be secured to the throw bar--they remained pinned against a block in the middle that pushed the points to one position or the other.

Do you have any photos of this installation?  I'm not quite grasping how the spring action is supposed to work, nor how the points don't need to be secured to the throw bars.  But I'm intrigued!

Thx,
-gfh

VonRyan

  • Crew
  • *
  • Posts: 3083
  • Gender: Male
  • Running on fumes
  • Respect: +641
Re: Taking the Plunge on Turnout Construction
« Reply #33 on: July 12, 2013, 05:50:24 PM »
0
In your opinion. I have had different experiences. But I suppose they don't count.

I suppose they do.


-Cody F.
Cody W Fisher  —  Wandering soul from a bygone era.
Tired.
Fighting to reclaim shreds of the past.

DKS

  • The Pitt
  • Crew
  • *
  • Posts: 13424
  • Respect: +7026
Re: Taking the Plunge on Turnout Construction
« Reply #34 on: July 12, 2013, 06:39:32 PM »
0
Do you have any photos of this installation?  I'm not quite grasping how the spring action is supposed to work, nor how the points don't need to be secured to the throw bars.  But I'm intrigued!

Photos are a little scarce, as the last turnouts I built this way have been permanently incorporated into a diorama. The few photos I have aren't very informative, so the following image should help illustrate the functional concepts:



The whole idea was to find a way to move hinged points without having to rigidly attach them to any kind of throw rod or bar. This eases the stresses placed on the points as they move. The illustration shows a slightly more refined design; the photos are of a proof-of-concept unit that lacks some parts that make assembly easier, in particular the blocks that adjust the pivot rod on the underside of the switch assembly.





Incidentally, the whole switch is built on a 1/8-inch thick sheet styrene substrate. To enhance electrical performance, I soldered feeder wires to the pivot rods so the points got current directly. Although the switches I built this way worked flawlessly, the drawback was their fairly complex assembly procedure, plus the need to assemble the switches on a substrate at the workbench, and then incorporate them into the rest of the track on the layout.
« Last Edit: July 12, 2013, 06:53:48 PM by David K. Smith »

peteski

  • Crew
  • *
  • Posts: 32815
  • Gender: Male
  • Honorary Resident Curmudgeon
  • Respect: +5264
    • Coming (not so) soon...
Re: Taking the Plunge on Turnout Construction
« Reply #35 on: July 12, 2013, 06:54:00 PM »
0
Taking all of this in (and never having build a turnout myself yet), I really like the idea of using continuous closure/point rail and then simply notching the base of the rail to make the rail more flexible.  After all, don't the 1:1 turnouts have continuous closure/pint rails which simply flex when the points are thrown?  I don't think they have any sort of a hinge.

DKS' steel-rod hinge idea is very interesting (and as usual, innovative) but to me it seems like a major overkill.
. . . 42 . . .

DKS

  • The Pitt
  • Crew
  • *
  • Posts: 13424
  • Respect: +7026
Re: Taking the Plunge on Turnout Construction
« Reply #36 on: July 12, 2013, 06:56:59 PM »
0
Taking all of this in (and never having build a turnout myself yet), I really like the idea of using continuous closure/point rail and then simply notching the base of the rail to make the rail more flexible.  After all, don't the 1:1 turnouts have continuous closure/pint rails which simply flex when the points are thrown?  I don't think they have any sort of a hinge.

Most 1:1 switches are hinged. Usually continuous rail switches are found on longer mainline switches.

Here's a switch with hinged points:



Here's a continuous rail switch:

« Last Edit: July 12, 2013, 06:59:05 PM by David K. Smith »

peteski

  • Crew
  • *
  • Posts: 32815
  • Gender: Male
  • Honorary Resident Curmudgeon
  • Respect: +5264
    • Coming (not so) soon...
Re: Taking the Plunge on Turnout Construction
« Reply #37 on: July 12, 2013, 07:07:10 PM »
0
DKS, thanks for the educational photo.  So, both types are out there in the 1:1 world.
. . . 42 . . .

wcfn100

  • Crew
  • *
  • Posts: 8837
  • Respect: +1214
    • Chicago Great Western Modeler
Re: Taking the Plunge on Turnout Construction
« Reply #38 on: July 12, 2013, 07:29:22 PM »
0
Take note of all the extra stuff needed for the continuous rail points to keep the rails where they're supposed to be.

Jason

jagged ben

  • Crew
  • *
  • Posts: 3244
  • Respect: +500
Re: Taking the Plunge on Turnout Construction
« Reply #39 on: July 12, 2013, 10:49:24 PM »
0
Those photos tell me that continuous points are fine for large turnouts on the mainline, but hinged points should be considered for smaller turnouts in yards and spurs.  My one worry about hinged points is electrical contact.  I've forgotten what Fast Tracks suggests. 

GaryHinshaw

  • Global Moderator
  • Crew
  • *
  • Posts: 6332
  • Respect: +1856
Re: Taking the Plunge on Turnout Construction
« Reply #40 on: July 13, 2013, 01:22:14 PM »
0
Thanks for the diagram David, now I get what you're doing.  One follow-up question: do you set the springs so the tension on each point is towards the centre-line of the track or towards the stock rail? Given the throw-bar design, it would seem to be towards the center.

-gfh

DKS

  • The Pitt
  • Crew
  • *
  • Posts: 13424
  • Respect: +7026
Re: Taking the Plunge on Turnout Construction
« Reply #41 on: July 13, 2013, 04:03:31 PM »
0
Thanks for the diagram David, now I get what you're doing.  One follow-up question: do you set the springs so the tension on each point is towards the centre-line of the track or towards the stock rail? Given the throw-bar design, it would seem to be towards the center.

Towards the center it is.

robert3985

  • Crew
  • *
  • Posts: 3119
  • Respect: +1495
Re: Taking the Plunge on Turnout Construction
« Reply #42 on: July 14, 2013, 03:58:42 PM »
0
DKS's scheme is similar to Andy Reichert's stainless, no-solder throwbars.  However, Andy's uses the springiness of non-hinged closure rail/closure point to get the non-pushed point to follow the throwbar, opening up a gap at the headblocks.

The nice thing about DKS's scheme is that you get the appearance of hinged closure points if that's what you're modeling.

The nice thing about Andy's scheme is that it is way simple, but you don't get any intimation of hinged closure points, especially when sighting down the track and seeing no "kink" at the heel block hinges.

Those of you who haven't built turnouts before should also know that one of the things that's important at the closure points is registering them so they're always at the same height as the adjacent stock rails.  That's one of the things that simply soldering them to a PCB throwbar does, the top surface of the PCB throwbar rubs against the underside of the stock rails, keeping the soldered-on closure points even with the tops of the stock rails, but allowing them to shift back and forth at the switch.

I'm assuming DKS's "wire rod throwbar" also rubs against the underside of the stock rails, to keep the closure points at the right height (if not, please 'splain how you do that, or if you think it's necessary).

Andy's utilizes a bent "finger" which fits over the top of the foot of the rail, holding it against the PCB "holder" which the two "throwbars" are attached to by inserting each into two holes drilled into the "holder".  The "holder" rubs against the underside of the stock rails, which combined with the fingers designed into the etched parts, holds the closure rails down.

My design allows the PCB "throwbar" to be in positive control of the closure points, but allows them to swivel, so the heel block hinges can be either precise-close-tolerance hinges like the notched hinges or DKS's, or hinges that allow slippage as do hinges made from rail joiners or Proto87 Stores etched heel block hinges.

I don't know if it's got through to some readers here, so I'll say it again:  A rigid parallelogram isn't what you want between the heel block hinges and the throwbar.  There MUST be some "give", either by having long rails (as in turnouts with free-floating, non-hinged rails between the frog and throwbar), flexible rails (code 40) or having "slippage" at the hinges (rail joiner hinges or Proto87 Stores' hinges)...OR by having a hinged closure point attachment protocol, like DKS's, Andy's or mine.  A short, stiff switch, such as having notched hinges and soldered-to-a-PCB-throwbar protocol joining closure points to a PCB throwbar, will result in the points breaking off the throwbar periodically as the joint is continually stressed.

I'll do some sketches and post 'em later tonight for clarity.

DKS

  • The Pitt
  • Crew
  • *
  • Posts: 13424
  • Respect: +7026
Re: Taking the Plunge on Turnout Construction
« Reply #43 on: July 14, 2013, 05:23:42 PM »
0
I'm assuming DKS's "wire rod throwbar" also rubs against the underside of the stock rails, to keep the closure points at the right height (if not, please 'splain how you do that, or if you think it's necessary).

Nope, no rubbin'. The steel pivot rods hold the points in vertical alignment quite nicely. The hole through which the rods pass are snug and there is very little play in the points.