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Author Topic: Working Wig-Wag
Charlie

Posts: 269
Post Working Wig-Wag
on: February 24, 2020,
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For my previous layout, I had made a couple lighted working SP style "Magnetic Wigwag Flagman" highway crossing signals. One of these signals was reworked with a new mechanism and banner light a few years ago and installed on the new layout as a testing sample for some signal improvements and also to try out a new (to me) detection circuit. This second signal has finally made it to the workbench after siting on a shelf for the last 20 years. So now behind the banner's red lens is a red 603 surface mount LED from Richmond Controls. The voltage regulator circuit required for the 1-1/2 volt mini bulb has now been replaced with just one 1.5k ohm resistor. Except for a new push rod link, the rest of the original mechanism is reused.

The second photo shows the mechanism to operate the signal consisting of a 12V DC motor, NWSL 28:1 HO gear box, gear axle link to the banner push rod, and a cam to open the snap action switch. The purpose for the cam and switch is to finish the banner's arc to the vertical down position when the train clears the circuit and the signal is turned off. The prototype wigwag was powered by two alternating electromagnets forcing the banner to swing from side to side. When off, gravity forced the banner to hang vertically.

The road crossing where this signal is intended is double tracked. Common practice for the SP was to use two wigwag signals for a road crossing two or more tracks. I'll use the other original mechanism plus a partially built signal I found in my parts box to construct the second signal for this crossing.

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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: February 25, 2020,
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As mentioned previously, I'm building the second wigwag needed for this double track crossing using an old partially built signal. For reasons now forgotten, I didn't build the model's signal mast and cantilever structure exactly to match the prototype. The model's mast should have used 3/32" tubing instead of 1/8" and 1/16" angle for the cantilever. It may have been a convenience of available brass shapes and providing space for wiring. An SP drawing for this standard crossing wigwag was published in volume 2 of "Southern Pacific Lines Common Standard Plans" if you have access to a copy.

The photo shows how the steel .010" diameter push rod is guided from the mast inside the cantilever brace to the rocker arm inside the motor house.

The photo also shows the LED wire access hole in the front face of the motor house. More on the motor house next.

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Martin
Administrator
Posts: 910
Post Re: Working Wig-Wag
on: February 25, 2020,
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Neatly done!

Want a balloon?

Charlie

Posts: 269
Post Re: Working Wig-Wag
on: February 26, 2020,
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The wigwag motor housing is also constructed from brass shapes: 1/4" square tube, 1/32"x1/4" and 1/16"x1/4" flat bar. The 1/16" thick bar is soldered at the rear end of the housing to support a 00-90 taped thread . The roof is a rectangular section cut out of 17/32" diameter brass tube. The rocker arm is made from 1/16" square brass tubing taped at one end for a 00-90 thread. A #76 drill makes the hole for the steel push rod 3/32" from the threaded hole. Shaping the push rod end of the rocker where it comes in contact with the motor housing inside wall is critical to allow the banner to swing through its full 62 degree arc. Once the rocker is checked out for the amount of swing arc, it is soldered to the 00-90 flat head screw. The roof will be glued on as a very last step before painting.
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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: February 26, 2020,
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The prototype banner disc is 21" diameter and the lens is 6-1/2" diameter. Center of the lens is 28-3/4" from the pivot point. I had cut my banner disc from 1/64"x 1/2" flat brass bar. And used 3/16" outside diameter tubing for the light housing in order to fit the 1-1/2 volt mini bulb inside I was then using. Now, the size 603 LED will permit using a closer to scale diameter tubing for the light housing.

The top of the banner disc is slotted to fit the .047" diameter brass tube for the banner arm and wire conduit.

The banner assembly was temporally attached to the flat head of the pivot screw in the previous photos to check the operation. It will be permanently soldered to the pivot after the LED and is installed the the LED wires have been threaded through the arm, motor housing, and out the bottom of the signal.

Charlie

Posts: 269
Post Re: Working Wig-Wag
on: February 27, 2020,
Quote

The SP style wigwag has steps bolted to the mast. This was simulated here with 1/32" x 1/4" brass bar soldered to the mast and then filed down to the shape shown in the photo.

This particular model has a resin casting of the Magnetic Wigwag Flagman relay case. The photo is of the prototype at the railroad museum in Sacramento, CA. The railroads also used standard block signal relay cases or a braced flange to support the signal on a concrete foundation.

The hole in the side of the mast tube below the relay case is an exit for the LED wiring. Below the hole is the lower guide for the .010" diameter steel push rod.

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Jay-
Criswell

Posts: 109
Post Re: Working Wig-Wag
on: February 27, 2020,
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Charlie,

Thank you for sharing.

Jay

Charlie

Posts: 269
Post Re: Working Wig-Wag
on: February 28, 2020,
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The twisted LED wires have been threaded through the motor housing, mast, and out at the exit hole below the signal base. In the motor housing, the wire is in a small loop to provide slack as the banner swings. After checking that the LED lights and verifying the swing arc, the banner was soldered to the flat head screw.

I turned the original wigwag bells from 1/4" diameter brass rod. However, for this signal I used a resin cast bell. I attached it to the back of the motor housing with a very small amount of epoxy being very careful to avoid getting any of the epoxy in the screw hole.

The motor housing roof was also attached with a small amount of glue and the signal prepared for painting. In the photos, the banner has already been painted with the white base coat.

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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: February 29, 2020,
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Both of the original wigwag signals were set up with vertically hung mechanisms as shown on the first post. As I wanted to increase the clearance between this mechanism and the lower level layout tracks, it was necessary to modify the mechanism to hang horizontally.

The cam and snap switch could be left as is, but the apparatus to swing the signal banner needed to be moved to the opposite side of the mounting block as shown in the photos. A new eccentric was pressed onto the other end of the worm gear axle rotated 90 degrees from the original position as located by the hole in the snap switch cam.

The link between the eccentric and push rod is slotted at one end to allow for fine adjustment of swing motion before soldering the push rod tube in place. All this fiddly stuff is done at the workbench. Only connecting three wires to the terminal strip and adding scenery ground cover needs to be done at the layout.

A 1/8" thick rectangular styrene plate sized to bridge a rectangular hole cut into the plywood/soundboard sandwich track base will support the mechanism and signal. The base of the signal itself is secured to the styrene with epoxy.

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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 1, 2020,
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The wigwag signal is finished and awaiting a hole to be cut in the plywood for the installation.

Great timing as the detection circuit that will operate these two wigwag signals has just arrived. So more on that at a later date.

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Jay-
Criswell

Posts: 109
Post Re: Working Wig-Wag
on: March 2, 2020,
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Charlie,

Thanks again for sharing this with us. I want to spend some time studying all of this.

Jay

Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 2, 2020,
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Jay,
As I mentioned at the start of this post, these particular wigwags were prototypes from 30 years ago before I had gathered very much info. Later signals were constructed on 3/32" diameter masts and with 1/16" brass angle as pictured below. Secondly, Irish Tracklayer has since brought out some very nice brass castings for the steps attached to the mast.

Also, the Maxon motors used here are somewhat over the top for this application. They happen to be a lucky find in a electronics surplus store bin at a few $ apiece. Smaller good quality motors would also work.

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Jay-
Criswell

Posts: 109
Post Re: Working Wig-Wag
on: March 2, 2020,
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Yeah, I thought about teasing you for your motor selection but wasn't sure you'd appreciate me pointing out the overkill.

Overall, it's really cool. John has one on the layout and it's always fun to watch it operate.

Jay

Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 5, 2020,
Quote

I've attached a diagram to explain the wiring circuit that operates these wigwag signals. Either AC or DC can be used for power and the bridge rectifier takes care of the polarity for the motor and LED. The cam operated snap action switch assures the banner will stop at the proper orientation (vertical in this case).

The exact voltage to get a realistic swing cycle depends on the motor and gear box ratio. I use about 6 volts for the signals shown in this post.

Terminals 1 and 2 are connected to one side of the signal power source and G is the ground or common. Terminal 1 is connected to the "On/Off switch" on the train detection device.
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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 9, 2020,
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I have an earlier version of the AZATRAX infrared train detector (MRX-1) operating a single wigwag signal since 2009 and have been quite happy with its trouble free operation. The current version of AZATRAX's infrared train detector is the MRX-3. This detector is setup to operate flashing light crossing signals, crossing gates, crossing bells, and although not specified in the instructions, wigwag signals as well.

The wiring diagram for a single wigwag signal is shown in the attached schematic. The relay contact in the MRX-3 train detector is rated at 0.35 amp maximum current. The Maxon motor plus LED used on this wigwag draws just under 0.1 amps.

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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 11, 2020,
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No scenery yet, but the wigwags are in place on the double track crossing. The wiring diagram for two wigwags is basically the same as the single with the exception of the addition of two diodes.

For train detection on two tracks, I used eight AZATRAX infrared detector sets as trains run either direction on both tracks. Six of the detector sets are included as part of the MRX3 circuit board. The other two detector sets are MRD1 single detectors connected back to MRX3 terminals. The AZATRAX web site has examples of detector arrangements for a variety of track configurations.

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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 12, 2020,
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One more photo.

Next a few other examples.
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Charlie

Posts: 269
Post Re: Working Wig-Wag
on: March 13, 2020,
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The Magnetic Signal Co. also offered their crossing signal in an Upper Quadrant design. A couple of examples from the ATSF are shown below. Working O scale models of this type signal can use the same type mechanism as described in this post.

I've enjoyed reading and posting on this OST forum and I'm very sorry to see it go.

Many thanks OST and White River,
Charlie Morrill

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Martin
Administrator
Posts: 910
Post Re: Working Wig-Wag
on: March 13, 2020,
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I've enjoyed reading and posting on this OST forum and I'm very sorry to see it go.

As am I, but I knew years ago it would eventually happen after Joe let me know how he had cudgeled the original site together - some baling wire and chewing gum was involved....

Want a balloon?

Tom-
Dempsey

Posts: 124
Post Re: Working Wig-Wag
on: March 14, 2020,
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I shall miss the intermittent contacts with you folks.

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