SWITCH MACHINES

[NW Modeling List]

When I began my layout 25 years ago, I used the twin coil type switch machines; since I wanted them "hidden" this required mounting them under the layout; I used the Rix mounting fixture for this.  I had some of these machines from a previous layout and bought some used ones at a train show.  They required 12 volts DC to throw and they would "snap" the points over with quite a bit of force. 



Eventually, I tried some of the Tortoise switch machines and have never looked back.  I replaced all of the twin coil types with the Tortoise machines. I do not use the edge connectors for attaching wires to the machines; I prefer to solder the wires directly to the machines contact pads.  I also use .032 piano wire for the actuating rod, rather than the .025 that is included with the machines.  My roadbed and subroadbed are 1 inch thick; I find the heavier wire solves any problems related to the thickness of my roadbed.  I also drill the clearance hole in the roadbed 3/8" instead of the 1/4" recommended. 



To mount the machine I put a piece of double sided foam tape on the top of it; I then slide the actuating rod into the clearance hole and through the center point of the turnout's throw rod.  I make certain the rod is straight up (if I am under the layout I do this with a helper) and not leaning in any direction; once satisfied the rod is straight, I press the machine and the double sided tape to the subroadbed.  I then use a power pack with test leads to make certain the Tortoise throws in both directions with sufficient tension on the points.  I have found that by making certain the actuating rod is "straight up" before pressing the machine in place will almost guarantee a perfect mount every time.  If for some reason the machine doesn't throw the points in both directions to my satisfaction, it is easy to remove the machine and reposition it. 



Once I'm satisfied the machine is throwing the points property, I then use screws to permanently mount the machine to the underside of the subroadbed. 



Although I have never had a Tortoise fail, the manfacturer provides a 9 year warranty. 



Jim Brewer 

Glenwood MD 


----- Original Message ----- 
From: "NW Modeling List" <nw-modeling-list at nwhs.org> 
To: nw-modeling-list at nwhs.org 
Sent: Monday, May 16, 2011 12:02:04 AM 
Subject: Re: SWITCH MACHINES 


The layout I work and operate on, Carl Winkler's, was built in the late 60's. If any of you were at the national NMRA convention in St. Louis in 2001 and went on the layout bus tours, you may have been there. The layout has well over a hundred twin coils that are NJ International style. Due to age and heavy use we probably replace three or so a year. The problem is, that style of twin coil switch machine is not made anymore to my knowledge. If I am mistaken about that please let me know who is making them. We use a powered probe to energize brass pins in the schematic on the control panel to throw them. They work very well, but are not scale speed like the Tortoise. 
Doug Langlitz 








-----Original Message----- 
From: NW Modeling List <nw-modeling-list at nwhs.org> 
To: 'NW Modeling List' <nw-modeling-list at nwhs.org> 
Sent: Sun, May 15, 2011 8:30 pm 
Subject: RE: SWITCH MACHINES 



I'll throw in my 2 cents Ed. 

I help build, maintain and operate a large HO layout (Tom Enloe's Pacific Northwestern). Typically I operate as yardmaster in a 12 track double ended yard with station facilities off one end and engine facilities off the other. I would say that there are approximately 50 switch machines in this portion of the layout. They are roughly split between Circuitron Tortoise machines and Scale Shops switch machines. 

Tortoises: Once installed, the Tortoise machines are very durable and reliable. Care is required in the installation in order to get them centered and set parallel to the throw of the points, but is not difficult. They are quiet and realistically slow in operation. In the years that I have been with this layout I have not known a Tortoise to fail. Tortoises are used in all new construction and most of the modeled railroad has been built with or retrofitted to them. I am also retrofitting my own much smaller layout with them from Caboose Hobbies hand throws and would note that they are much easier to install centered under the points as the turnout is installed (or at least drill the hole for the throw wire) rather than retrofitting them to the side or with bent wire mechanisms after the turnout is in place. 

Scale Shops: These are threaded shaft motor drives where the moving dolly throws the turnout and makes/breaks a set of contacts, some of which are part of the motor wiring and stop the motor at the end of the throw. They are not as precise regarding the mounting as we used all bent wire throws which left us some adjustment after mounting. Unfortunately I do not rank them as high in reliability. Since there is some momentum to the motor and dolly, they can slightly overrun the cutoff point of the contacts. Then when thrown to the other direction they just whine at very high frequency. Some of the more senior members can't hear this whine and don't know why the switch didn't throw. We have also had the contacts get bumped (they are exposed) which misaligned them or pushed one contact set into another. On one or two occasions we have had the motor come loose from the base and had a 50/50 success rate reattaching them. Another observation is that they are somewhat noisy for the short time they are active and don't contribute to the realism of the layout (but it's easy to tell if they are working). 

Twin coils: The PNW staging yard was built with approximately 20 twin coil solenoid switch machines. I have not peeked under there to see which brand they are. A few have been replaced but most are still working after 20 years or so. 

This layout has been in existence for many years and all 3 of these switch machine types have served well. Given a choice I have gone with the Tortoise on my layout. 

Don Trettel 
Roanoke native now living near Seattle. 




From: nw-modeling-list-bounces at nwhs.org [ mailto:nw-modeling-list-bounces at nwhs.org ] On Behalf Of NW Modeling List 
Sent: Sunday, May 15, 2011 7:26 AM 
To: NW Modeling 
Subject: SWITCH MACHINES 


I sent out a note a while ago about anyone with positive experiences with switch machines (HO).  Don't recall if anyone wrote back but if you've had good luck installation, operation and mainteance wise would sure like some tips. 
  
Thanks! 

Ed Svitil 
Norfolk & Western Railway 
  
  




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